Remove empty elements from an array in Javascript

Question

How do I remove empty elements from an array in JavaScript    Is there a straightforward way  or do I need to loop through it and remove them manually

User · Answer

Try this   Pass it your array and it will return with empty elements removed    Updated to address the bug pointed out by Jason  function removeEmptyElem ary        for  var i   ary length - 1  i  gt   0  i--            if  ary i     undefined                 ary splice i  1                              return ary

User · Answer

If you ve got Javascript 1 6 or later you can use Array filter using a trivial return true callback function  e g    arr   arr filter function     return true        since  filter automatically skips missing elements in the original array   The MDN page linked above also contains a nice error-checking version of filter that can be used in JavaScript interpreters that don t support the official version   Note that this will not remove null entries nor entries with an explicit undefined value  but the OP specifically requested  missing  entries

User · Answer

You may find it easier to loop over your array and build a new array out of the items you want to keep from the array than by trying to loop and splice as has been suggested  since modifying the length of the array while it is being looped over can introduce problems   You could do something like this   function removeFalsyElementsFromArray someArray        var newArray           for var index   0  index  lt  someArray length  index              if someArray index                 newArray push someArray index                        return newArray      Actually here is a more generic solution   function removeElementsFromArray someArray  filter        var newArray           for var index   0  index  lt  someArray length  index              if filter someArray index      false                newArray push someArray index                        return newArray        then provide one or more filter functions that will     filter out the elements based on some condition  function isNullOrUndefined item        return  item    null    typeof item      undefined          then call the function like this  var myArray    1 2  3  3      4  4  5  6       var results   removeElementsFromArray myArray  isNullOrUndefined       results     1 2 3 3 4 4 5 6    You get the idea - you could then have other types of filter functions  Probably more than you need  but I was feeling generous

User · Answer

This works  I tested it in AppJet  you can copy-paste the code on its IDE and press  reload  to see it work  don t need to create an account      appjet version 0 1    function Joes remove someArray        var newArray           var element      for  element in someArray           if someArray element   undefined                 newArray push someArray element                        return newArray     var myArray2    1 2  3  3   0   4  4  5  6        print  Original array    myArray2   print  Clenased array    Joes remove myArray2        Returns   1 2 3 3 0 4 4 5 6

User · Answer

EDIT  This question was answered almost nine years ago when there were not many useful built-in methods in the Array prototype   Now  certainly  I would recommend you to use the filter method   Take in mind that this method will return you a new array with the elements that pass the criteria of the callback function you provide to it   For example  if you want to remove null or undefined values     x000D   x000D  var array    0  1  null  2      3  undefined  3       4   4   5   6       x000D   x000D  var filtered   array filter function  el    x000D    return el    null  x000D      x000D   x000D  console log filtered   x000D   x000D   x000D    It will depend on what you consider to be  empty  for example  if you were dealing with strings  the above function wouldn t remove elements that are an empty string   One typical pattern that I see often used is to remove elements that are falsy  which include an empty string     0  NaN  null  undefined  and false   You can pass to the filter method  the Boolean constructor function  or return the same element in the filter criteria function  for example   var filtered   array filter Boolean     Or  var filtered   array filter function el    return el        In both ways  this works because the filter method in the first case  calls the Boolean constructor as a function  converting the value  and in the second case  the filter method internally turns the return value of the callback implicitly to Boolean   If you are working with sparse arrays  and you are trying to get rid of the  holes   you can use the filter method passing a callback that returns true  for example    x000D   x000D  var sparseArray    0      1          2        3   x000D      cleanArray   sparseArray filter function      return true     x000D   x000D  console log cleanArray        0  1  2  3   x000D   x000D   x000D    Old answer  Don t do this   I use this method  extending the native Array prototype   Array prototype clean   function deleteValue      for  var i   0  i  lt  this length  i          if  this i     deleteValue                   this splice i  1         i--              return this      test   new Array      One    Two        Three        Four   clean      test2    1  2   3   3       4   4   5   6       test2 clean undefined     Or you can simply push the existing elements into other array      Will remove all falsy values  undefined  null  0  false  NaN and     empty string  function cleanArray actual      var newArray   new Array      for  var i   0  i  lt  actual length  i          if  actual i           newArray push actual i                return newArray     cleanArray  1  2   3   3       4   4   5   6

User · Answer

The best way to remove empty elements  is to use Array prototype filter    as already mentioned in other answers   Unfortunately  Array prototype filter   is not supported by IE lt 9  If you still need to support IE8 or an even older version of IE  you could use the following polyfill to add support for Array prototype filter   in these browsers    if   Array prototype filter      Array prototype filter   function fun    thisArg           use strict       if  this     void 0    this     null          throw new TypeError              var t   Object this       var len   t length  gt  gt  gt  0      if  typeof fun      function           throw new TypeError              var res           var thisArg   arguments length  gt   2   arguments 1    void 0      for  var i   0  i  lt  len  i            if  i in t            var val   t i           if  fun call thisArg  val  i  t               res push val                               return res

User · Answer

This might help you   https   lodash com docs 4 17 4 remove  var details                                   reference   ref-1                   description   desc-1                   price  1                                  reference                      description                      price                                      reference   ref-2                   description   desc-2                   price  200                                  reference   ref-3                   description   desc-3                   price  3                                  reference                      description                      price                                       scope removeEmptyDetails details           expect details length  toEqual 3       scope removeEmptyDetails   function details                 remove details  function detail                   return    isEmpty detail reference   amp  amp    isEmpty detail description   amp  amp    isEmpty detail price

User · Answer

When using the highest voted answer above  first example  i was getting individual characters for string lengths greater than 1  Below is my solution for that problem   var stringObject         some string yay            Other string yay    stringObject   stringObject filter function n   return n length  gt  0      Instead of not returning if undefined  we return if length is greater than 0  Hope that helps somebody out there   Returns    some string yay    Other string yay

User · Answer

With Underscore Lodash   General use case     without array  emptyVal  otherEmptyVal     without  1  2  1  0  3  1  4   0  1     With empties     without   foo    bar        baz            foobar         -- gt    foo    bar    baz    foobar     See lodash documentation for without

User · Answer

You may find it easier to loop over your array and build a new array out of the items you want to keep from the array than by trying to loop and splice as has been suggested  since modifying the length of the array while it is being looped over can introduce problems   You could do something like this   function removeFalsyElementsFromArray someArray        var newArray           for var index   0  index  lt  someArray length  index              if someArray index                 newArray push someArray index                        return newArray      Actually here is a more generic solution   function removeElementsFromArray someArray  filter        var newArray           for var index   0  index  lt  someArray length  index              if filter someArray index      false                newArray push someArray index                        return newArray        then provide one or more filter functions that will     filter out the elements based on some condition  function isNullOrUndefined item        return  item    null    typeof item      undefined          then call the function like this  var myArray    1 2  3  3      4  4  5  6       var results   removeElementsFromArray myArray  isNullOrUndefined       results     1 2 3 3 4 4 5 6    You get the idea - you could then have other types of filter functions  Probably more than you need  but I was feeling generous

User · Answer

foo    0  1  2        false  3   four   null   foo filter function e        return e     0    0    e      returns   0  1  2  3   four

User · Answer

I m simply adding my voice to the above    call ES5 s Array  filter   with a global constructor    golf-hack  but I suggest using Object instead of String  Boolean  or Number as suggested above   Specifically  ES5 s filter   already doesn t trigger for undefined elements within the array  so a function that universally returns true  which returns all elements filter   hits  will necessarily only return non-undefined elements    gt   1  5 6 772 5 24 5  abc  function     1 5  3  filter function   return true    1  5  6  772  5  24  5   abc   function       1  5  3    However  writing out     function   return true    is longer than writing     Object   and the return-value of the Object constructor will be  under any circumstances  some sort of object  Unlike the primitive-boxing-constructors suggested above  no possible object-value is falsey  and thus in a boolean setting  Object is a short-hand for function   return true     gt   1  5 6 772 5 24 5  abc  function     1 5  3  filter Object   1  5  6  772  5  24  5   abc   function       1  5  3

User · Answer

Simple ES6    a   b        w   b   filter v   gt  v

User · Answer

I m simply adding my voice to the above    call ES5 s Array  filter   with a global constructor    golf-hack  but I suggest using Object instead of String  Boolean  or Number as suggested above   Specifically  ES5 s filter   already doesn t trigger for undefined elements within the array  so a function that universally returns true  which returns all elements filter   hits  will necessarily only return non-undefined elements    gt   1  5 6 772 5 24 5  abc  function     1 5  3  filter function   return true    1  5  6  772  5  24  5   abc   function       1  5  3    However  writing out     function   return true    is longer than writing     Object   and the return-value of the Object constructor will be  under any circumstances  some sort of object  Unlike the primitive-boxing-constructors suggested above  no possible object-value is falsey  and thus in a boolean setting  Object is a short-hand for function   return true     gt   1  5 6 772 5 24 5  abc  function     1 5  3  filter Object   1  5  6  772  5  24  5   abc   function       1  5  3

User · Answer

var a     a1  1  children    a1  2   undefined   a1  3     undefined   a1  5   undefined   a1  6   function removeNilItemInArray arr        if   arr     arr length  return      for  let i   0  i  lt  arr length  i              if   arr i                 arr splice i   1               continue                    removeNilItemInArray arr i  children           var b   a  removeNilItemInArray a      Always keep this memory zone console log b

User · Answer

Here is an example using variadic behavior  amp  ES2015 fat arrow expression   Array prototype clean   function       var args      slice call arguments     return this filter item   gt  args indexOf item      -1          Usage var arr        undefined  3   yes   undefined  undefined       arr clean undefined           3   yes        arr clean undefined           3   yes

User · Answer

I needed to do this same task and came upon this thread  I ended up using the array  join  to create a string using a     separator  then doing a bit of regex to -  1  replace      or more with just one      2  replace preceding     with nothing    and similarly  3  replace and ending     with nothing         then using array  split  to make a cleaned-up array -  var myArr   new Array        a   b      c                           e       var myStr        myStr   myArr join        myStr   myStr replace new RegExp      g        myStr   myStr replace new RegExp     i       myStr   myStr replace new RegExp     i       myArr   myStr split        alert  myArr     myArr join             or in 1 line of code -  var myArr   new Array        a   b      c                           e        myArr   myArr join      replace new RegExp      g       replace new RegExp     i      replace new RegExp     i      split        alert  myArr     myArr join             or  extending the Array object  -  Array prototype clean   function       return this join      replace new RegExp      g       replace new RegExp     i      replace new RegExp     i      split           var myArr   new Array        a   b      c                           e        alert  myArr     myArr clean   join

User · Answer

Since nobody else mentioned it and most people have underscore included in their project you can also use   without array   values        without   text    string   null  null  null   text    null       gt    text    string    text

User · Answer

The clean way to do it   var arr    0 1 2  Thomas   false  false true null 3 4 undefined 5  end    arr   arr filter Boolean       1  2   Thomas    false   true  3  4  5   end

User · Answer

This might help you   https   lodash com docs 4 17 4 remove  var details                                   reference   ref-1                   description   desc-1                   price  1                                  reference                      description                      price                                      reference   ref-2                   description   desc-2                   price  200                                  reference   ref-3                   description   desc-3                   price  3                                  reference                      description                      price                                       scope removeEmptyDetails details           expect details length  toEqual 3       scope removeEmptyDetails   function details                 remove details  function detail                   return    isEmpty detail reference   amp  amp    isEmpty detail description   amp  amp    isEmpty detail price

User · Answer

If you ve got Javascript 1 6 or later you can use Array filter using a trivial return true callback function  e g    arr   arr filter function     return true        since  filter automatically skips missing elements in the original array   The MDN page linked above also contains a nice error-checking version of filter that can be used in JavaScript interpreters that don t support the official version   Note that this will not remove null entries nor entries with an explicit undefined value  but the OP specifically requested  missing  entries

User · Answer

Alnitak  Actually Array filter works on all browsers if you add some extra code  See below   var array        one  0    null 0 1 2 4  two     function isempty x   if x           return true    var res   array filter isempty   document writeln res toJSONString        gives    one  0 null 0 1 2 4  two       This is the code you need to add for IE  but filter and Functional programmingis worth is imo     This prototype is provided by the Mozilla foundation and   is distributed under the MIT license    http   www ibiblio org pub Linux LICENSES mit license  if   Array prototype filter      Array prototype filter   function fun     thisp            var len   this length      if  typeof fun     function         throw new TypeError         var res   new Array        var thisp   arguments 1       for  var i   0  i  lt  len  i                if  i in this                  var val   this i      in case fun mutates this         if  fun call thisp  val  i  this             res push val                      return res

User · Answer

Simple ways   var arr    1 2  3  -3 null  0  undefined 4  4  5  6         arr filter n   gt  n      1  2  3  -3  4  4  5  6   arr filter Number       1  2  3  -3  4  4  5  6   arr filter Boolean       1  2  3  -3  4  4  5  6    or -  only for single array items of type  text         1   2  3   4   undefined    5   join     split          output     1   2   3   4   5     or - Classic way  simple iteration  var arr    1 2 null  undefined 3  3   0           5  6           len   arr length  i   for i   0  i  lt  len  i         arr i   amp  amp  arr push arr i        copy non-empty values to the end of the array  arr splice 0   len       cut the array and leave only the non-empty values  arr     1 2 3 3    Object   5 6      via jQuery   var arr    1 2  3  3   0   4  4  5  6        arr     grep arr function n   return n    0    n      arr     1  2  3  3  0  4  4  5  6      UPDATE - just another fast  cool way  using ES6    var arr    1 2 null  undefined 3  3   0   4  4  5  6            temp        for let i of arr      i  amp  amp  temp push i      copy each non-empty value to the  temp  array  arr   temp   arr     1  2  3  3  4  4  5  6    Remove empty values    foo            null       3  true       1       undefined      gt     filter String        foo   null       3  true   1   Object     undefined      gt

User · Answer

var data    null  1 2 3   var r   data filter function i   return i    null         console log r         1 2 3

User · Answer

What about that   js gt   1 2  3  3   0   4  4  5  6      filter String  join      1 2 3 3 0 4 4 5 6

User · Answer

If you ve got Javascript 1 6 or later you can use Array filter using a trivial return true callback function  e g    arr   arr filter function     return true        since  filter automatically skips missing elements in the original array   The MDN page linked above also contains a nice error-checking version of filter that can be used in JavaScript interpreters that don t support the official version   Note that this will not remove null entries nor entries with an explicit undefined value  but the OP specifically requested  missing  entries

User · Answer

EDIT  This question was answered almost nine years ago when there were not many useful built-in methods in the Array prototype   Now  certainly  I would recommend you to use the filter method   Take in mind that this method will return you a new array with the elements that pass the criteria of the callback function you provide to it   For example  if you want to remove null or undefined values     x000D   x000D  var array    0  1  null  2      3  undefined  3       4   4   5   6       x000D   x000D  var filtered   array filter function  el    x000D    return el    null  x000D      x000D   x000D  console log filtered   x000D   x000D   x000D    It will depend on what you consider to be  empty  for example  if you were dealing with strings  the above function wouldn t remove elements that are an empty string   One typical pattern that I see often used is to remove elements that are falsy  which include an empty string     0  NaN  null  undefined  and false   You can pass to the filter method  the Boolean constructor function  or return the same element in the filter criteria function  for example   var filtered   array filter Boolean     Or  var filtered   array filter function el    return el        In both ways  this works because the filter method in the first case  calls the Boolean constructor as a function  converting the value  and in the second case  the filter method internally turns the return value of the callback implicitly to Boolean   If you are working with sparse arrays  and you are trying to get rid of the  holes   you can use the filter method passing a callback that returns true  for example    x000D   x000D  var sparseArray    0      1          2        3   x000D      cleanArray   sparseArray filter function      return true     x000D   x000D  console log cleanArray        0  1  2  3   x000D   x000D   x000D    Old answer  Don t do this   I use this method  extending the native Array prototype   Array prototype clean   function deleteValue      for  var i   0  i  lt  this length  i          if  this i     deleteValue                   this splice i  1         i--              return this      test   new Array      One    Two        Three        Four   clean      test2    1  2   3   3       4   4   5   6       test2 clean undefined     Or you can simply push the existing elements into other array      Will remove all falsy values  undefined  null  0  false  NaN and     empty string  function cleanArray actual      var newArray   new Array      for  var i   0  i  lt  actual length  i          if  actual i           newArray push actual i                return newArray     cleanArray  1  2   3   3       4   4   5   6

User · Answer

Simply one liner    1  false      undefined  2  filter Boolean       1  2    or using underscorejs org     filter  1  false      undefined  2   Boolean       1  2     or even    compact  1  false      undefined  2        1  2

User · Answer

Just ES6 and newer versions method  assume array is below    const arr    1 2 3 undefined 4 5 6 undefined 7 8 undefined undefined 0 9     Simple way    const clearArray   arr filter  i   gt  i

User · Answer

Misusing  the for     in  object-member  loop       Only truthy values appear in the body of the loop      --- Example ---------- var field        field 0     One   field 1    1  field 3    true  field 5    43 68  field 7     theLastElement      --- Example ----------  var originalLength      Store the length of the array  originalLength   field length   for  var i in field         Attach the truthy values upon the end of the array     field push field i          Delete the original range within the array so that    only the new elements are preserved  field splice 0  originalLength

User · Answer

Removing all empty elements  If an array contains empty Objects  Arrays  and Strings alongside other empty elements  we can remove them with    x000D   x000D  const arr           not    empty          key   value     0  1  null  2       here        3  undefined  3            4    4    5    6        x000D   x000D  let filtered   JSON stringify  x000D    arr filter  obj    gt    x000D      return   null  undefined      includes obj  x000D       filter  el    gt    x000D      return typeof el     object     Object keys el  length  gt  0 x000D       x000D    x000D   x000D  console log JSON parse filtered   x000D   x000D   x000D    Simple compacting  removing empty elements from an array   With ES6    x000D   x000D  const arr    0  1  null  2      3  undefined  3            4    4    5    6         x000D   x000D  let filtered   arr filter  obj    gt    return   null  undefined  includes obj     x000D   x000D  console log filtered  x000D   x000D   x000D    With plain Javascript -    x000D   x000D  var arr    0  1  null  2      3  undefined  3            4    4    5    6         x000D   x000D  var filtered   arr filter function  obj    return   null  undefined  includes obj     x000D   x000D  console log filtered  x000D   x000D   x000D

User · Answer

Alnitak  Actually Array filter works on all browsers if you add some extra code  See below   var array        one  0    null 0 1 2 4  two     function isempty x   if x           return true    var res   array filter isempty   document writeln res toJSONString        gives    one  0 null 0 1 2 4  two       This is the code you need to add for IE  but filter and Functional programmingis worth is imo     This prototype is provided by the Mozilla foundation and   is distributed under the MIT license    http   www ibiblio org pub Linux LICENSES mit license  if   Array prototype filter      Array prototype filter   function fun     thisp            var len   this length      if  typeof fun     function         throw new TypeError         var res   new Array        var thisp   arguments 1       for  var i   0  i  lt  len  i                if  i in this                  var val   this i      in case fun mutates this         if  fun call thisp  val  i  this             res push val                      return res

User · Answer

For removing holes  you should use arr filter      gt  true  arr flat 0     New in ES2019  check compatibility before using this  For removing hole  null  and  undefined  arr filter x   gt  x    null   For removing hole  and  falsy  null  undefined  0  -0  0n  NaN   quot  quot   false  document all  values  arr filter x   gt  x    x000D   x000D  arr      null   void 0   0  -0  0n  NaN  false      42   console log arr filter      gt  true        null   void 0   0  -0  0n  NaN  false      42  console log arr filter x   gt  x    null        0  -0  0n  NaN  false      42  console log arr filter x   gt  x        42  x000D   x000D   x000D

User · Answer

This is another way to do it   var arr     a    b   undefined  undefined   e   undefined   g   undefined   i        k   var cleanArr   arr join      split

User · Answer

If anyone is looking for cleaning the whole Array or Object this might help   var qwerty         test1  null      test2   somestring       test3  3      test4          test5            foo   bar             test6          test7  undefined      test8           test9  true      test10          test11    77   88        test12            foo   foo           bar                foo   q               bar                    foo 4                  bar                                     bob              var asdfg                yyyy   78  null  undefined true       x 6        2 3 5     function clean data obj        for  var key in obj               Delete null  undefined                  if  obj key      null    obj key      undefined    obj key            obj key                         delete obj key                        Delete empty object            Note   typeof Array is also object         if  typeof obj key       object   amp  amp  Object keys obj key   length  lt   0                delete obj key                        If non empty object call function again         if typeof obj key       object                clean data obj key                        return obj     var objData   clean data qwerty   console log objData   var arrayData   clean data asdfg   console log arrayData     Output   Removes anything that is null  undefined           empty object or empty array  jsfiddle here

User · Answer

Try this   Pass it your array and it will return with empty elements removed    Updated to address the bug pointed out by Jason  function removeEmptyElem ary        for  var i   ary length - 1  i  gt   0  i--            if  ary i     undefined                 ary splice i  1                              return ary

User · Answer

You may find it easier to loop over your array and build a new array out of the items you want to keep from the array than by trying to loop and splice as has been suggested  since modifying the length of the array while it is being looped over can introduce problems   You could do something like this   function removeFalsyElementsFromArray someArray        var newArray           for var index   0  index  lt  someArray length  index              if someArray index                 newArray push someArray index                        return newArray      Actually here is a more generic solution   function removeElementsFromArray someArray  filter        var newArray           for var index   0  index  lt  someArray length  index              if filter someArray index      false                newArray push someArray index                        return newArray        then provide one or more filter functions that will     filter out the elements based on some condition  function isNullOrUndefined item        return  item    null    typeof item      undefined          then call the function like this  var myArray    1 2  3  3      4  4  5  6       var results   removeElementsFromArray myArray  isNullOrUndefined       results     1 2 3 3 4 4 5 6    You get the idea - you could then have other types of filter functions  Probably more than you need  but I was feeling generous

User · Answer

this is my solution for clean empty fields   Start from fees object  get only avail attribute  with map  filter empty fields  with filter  parse results to integer  with map   fees map    e     gt  e avail   filter  v   gt  v        map  i   gt  parseInt  i

User · Answer

You can use filter with index and in operator  x000D   x000D  let a    1  2   3   let b   a filter  x i   gt  i in a    console log  a b    x000D   x000D   x000D

User · Answer

Simple ways   var arr    1 2  3  -3 null  0  undefined 4  4  5  6         arr filter n   gt  n      1  2  3  -3  4  4  5  6   arr filter Number       1  2  3  -3  4  4  5  6   arr filter Boolean       1  2  3  -3  4  4  5  6    or -  only for single array items of type  text         1   2  3   4   undefined    5   join     split          output     1   2   3   4   5     or - Classic way  simple iteration  var arr    1 2 null  undefined 3  3   0           5  6           len   arr length  i   for i   0  i  lt  len  i         arr i   amp  amp  arr push arr i        copy non-empty values to the end of the array  arr splice 0   len       cut the array and leave only the non-empty values  arr     1 2 3 3    Object   5 6      via jQuery   var arr    1 2  3  3   0   4  4  5  6        arr     grep arr function n   return n    0    n      arr     1  2  3  3  0  4  4  5  6      UPDATE - just another fast  cool way  using ES6    var arr    1 2 null  undefined 3  3   0   4  4  5  6            temp        for let i of arr      i  amp  amp  temp push i      copy each non-empty value to the  temp  array  arr   temp   arr     1  2  3  3  4  4  5  6    Remove empty values    foo            null       3  true       1       undefined      gt     filter String        foo   null       3  true   1   Object     undefined      gt

User · Answer

This is another way to do it   var arr     a    b   undefined  undefined   e   undefined   g   undefined   i        k   var cleanArr   arr join      split

User · Answer

foo    0  1  2        false  3   four   null   foo filter function e        return e     0    0    e      returns   0  1  2  3   four

User · Answer

ES6   let newArr   arr filter e   gt  e

User · Answer

Misusing  the for     in  object-member  loop       Only truthy values appear in the body of the loop      --- Example ---------- var field        field 0     One   field 1    1  field 3    true  field 5    43 68  field 7     theLastElement      --- Example ----------  var originalLength      Store the length of the array  originalLength   field length   for  var i in field         Attach the truthy values upon the end of the array     field push field i          Delete the original range within the array so that    only the new elements are preserved  field splice 0  originalLength

User · Answer

Another way to do it is to take advantage of the length property of the array   pack the non-null items on the  left  of the array  then reduce the length   It is an in-place algorithm -does not allocates memory  too bad for the garbage collector-  and it has very good best average worst case behaviour   This solution  compared to others here  is between 2 to 50 times faster on Chrome  and 5 to 50 times faster on Firefox  as you might see here   http   jsperf com remove-null-items-from-array  The code below adds the non-enumerable  removeNull  method to the Array  which returns  this  for daisy-chaining     var removeNull   function         var nullCount   0                 var length      this length       for  var i 0  len this length  i lt len  i      if   this i    nullCount             no item is null     if   nullCount    return this         all items are null     if  nullCount    length    this length   0  return this          mix of null    non-null     var idest 0  isrc length-1      length -  nullCount                       while  true                find a non null  source  slot on the right          while   this isrc      isrc--  nullCount--              if      nullCount    break            break if found all null             find one null slot on the left  destination           while   this idest     idest                    perform copy          this idest  this isrc            if    --nullCount    break           idest     isrc --             this length length       return this        Object defineProperty Array prototype   removeNull                      value   removeNull  writable   true  configurable   true

User · Answer

The clean way to do it   var arr    0 1 2  Thomas   false  false true null 3 4 undefined 5  end    arr   arr filter Boolean       1  2   Thomas    false   true  3  4  5   end

User · Answer

If using a library is an option I know underscore js has a function called compact   http   documentcloud github com underscore  it also has several other useful functions related to arrays and collections   Here is an excerpt from their documentation        compact array         Returns a copy of the array with all falsy values removed  In JavaScript  false  null  0      undefined and NaN are all falsy         compact  0  1  false  2      3             1  2  3

User · Answer

I needed to do this same task and came upon this thread  I ended up using the array  join  to create a string using a     separator  then doing a bit of regex to -  1  replace      or more with just one      2  replace preceding     with nothing    and similarly  3  replace and ending     with nothing         then using array  split  to make a cleaned-up array -  var myArr   new Array        a   b      c                           e       var myStr        myStr   myArr join        myStr   myStr replace new RegExp      g        myStr   myStr replace new RegExp     i       myStr   myStr replace new RegExp     i       myArr   myStr split        alert  myArr     myArr join             or in 1 line of code -  var myArr   new Array        a   b      c                           e        myArr   myArr join      replace new RegExp      g       replace new RegExp     i      replace new RegExp     i      split        alert  myArr     myArr join             or  extending the Array object  -  Array prototype clean   function       return this join      replace new RegExp      g       replace new RegExp     i      replace new RegExp     i      split           var myArr   new Array        a   b      c                           e        alert  myArr     myArr clean   join

User · Answer

This works  I tested it in AppJet  you can copy-paste the code on its IDE and press  reload  to see it work  don t need to create an account      appjet version 0 1    function Joes remove someArray        var newArray           var element      for  element in someArray           if someArray element   undefined                 newArray push someArray element                        return newArray     var myArray2    1 2  3  3   0   4  4  5  6        print  Original array    myArray2   print  Clenased array    Joes remove myArray2        Returns   1 2 3 3 0 4 4 5 6

User · Answer

this is my solution for clean empty fields   Start from fees object  get only avail attribute  with map  filter empty fields  with filter  parse results to integer  with map   fees map    e     gt  e avail   filter  v   gt  v        map  i   gt  parseInt  i

User · Answer

Just ES6 and newer versions method  assume array is below    const arr    1 2 3 undefined 4 5 6 undefined 7 8 undefined undefined 0 9     Simple way    const clearArray   arr filter  i   gt  i

User · Answer

For removing holes  you should use arr filter      gt  true  arr flat 0     New in ES2019  check compatibility before using this  For removing hole  null  and  undefined  arr filter x   gt  x    null   For removing hole  and  falsy  null  undefined  0  -0  0n  NaN   quot  quot   false  document all  values  arr filter x   gt  x    x000D   x000D  arr      null   void 0   0  -0  0n  NaN  false      42   console log arr filter      gt  true        null   void 0   0  -0  0n  NaN  false      42  console log arr filter x   gt  x    null        0  -0  0n  NaN  false      42  console log arr filter x   gt  x        42  x000D   x000D   x000D

User · Answer

var a     a1  1  children    a1  2   undefined   a1  3     undefined   a1  5   undefined   a1  6   function removeNilItemInArray arr        if   arr     arr length  return      for  let i   0  i  lt  arr length  i              if   arr i                 arr splice i   1               continue                    removeNilItemInArray arr i  children           var b   a  removeNilItemInArray a      Always keep this memory zone console log b

User · Answer

This one will only remove empty values and not falsey ones  which I think is more desirable   There is an option to also remove null values   This method should be much faster than using splice       function cleanArray a  removeNull            var i  l  temp               l   a length          if  removeNull                for  i   0  i  lt  l  i                      if  a i      undefined  amp  amp  a i      null                        temp push a i                                              else               for  i   0  i  lt  l  i                      if  a i      undefined                        temp push a i                                                      a length   0          l   temp length          for  i   0  i  lt  l  i                  a i    temp i                     temp length   0          return a            var myArray    1  2    3    3      0    null  false    NaN      4    4    5    6               cleanArray myArray       myArray

User · Answer

How about doing it this way       Removes all falsy values  arr   arr filter function array val       creates an anonymous filter func     var x   Boolean array val      checks if val is null     return x    true     returns val to array if not null

User · Answer

Simple ES6    a   b        w   b   filter v   gt  v

User · Answer

An in place solution   function pack arr       remove undefined values   let p   -1   for  let i   0  len   arr length  i  lt  len  i          if  arr i      undefined    if  p  gt   0    arr p    arr i   p           else if  p  lt  0  p   i       if  p  gt   0  arr length   p   return arr    let a    1  2  3  undefined  undefined  4  5  undefined  null  console log JSON stringify a   pack a  console log JSON stringify a

User · Answer

When using the highest voted answer above  first example  i was getting individual characters for string lengths greater than 1  Below is my solution for that problem   var stringObject         some string yay            Other string yay    stringObject   stringObject filter function n   return n length  gt  0      Instead of not returning if undefined  we return if length is greater than 0  Hope that helps somebody out there   Returns    some string yay    Other string yay

User · Answer

use filter to remove empty string in array    x000D   x000D  var s      1 201 karthikeyan K201 HELPER karthikeyan a limitlessmobil com 8248606269 7 14 2017 45680 TN-KAR24 8 800 1000 200 300 Karthikeyan 11 24 2017 Karthikeyan 11 24 2017 AVAILABLE r   x000D         x000D  var newArr   s filter function entry    return entry trim             x000D   x000D  console log newArr    x000D   x000D   x000D

User · Answer

An in place solution   function pack arr       remove undefined values   let p   -1   for  let i   0  len   arr length  i  lt  len  i          if  arr i      undefined    if  p  gt   0    arr p    arr i   p           else if  p  lt  0  p   i       if  p  gt   0  arr length   p   return arr    let a    1  2  3  undefined  undefined  4  5  undefined  null  console log JSON stringify a   pack a  console log JSON stringify a

User · Answer

var data    null  1 2 3   var r   data filter function i   return i    null         console log r         1 2 3

User · Answer

If anyone is looking for cleaning the whole Array or Object this might help   var qwerty         test1  null      test2   somestring       test3  3      test4          test5            foo   bar             test6          test7  undefined      test8           test9  true      test10          test11    77   88        test12            foo   foo           bar                foo   q               bar                    foo 4                  bar                                     bob              var asdfg                yyyy   78  null  undefined true       x 6        2 3 5     function clean data obj        for  var key in obj               Delete null  undefined                  if  obj key      null    obj key      undefined    obj key            obj key                         delete obj key                        Delete empty object            Note   typeof Array is also object         if  typeof obj key       object   amp  amp  Object keys obj key   length  lt   0                delete obj key                        If non empty object call function again         if typeof obj key       object                clean data obj key                        return obj     var objData   clean data qwerty   console log objData   var arrayData   clean data asdfg   console log arrayData     Output   Removes anything that is null  undefined           empty object or empty array  jsfiddle here

User · Answer

Filtering out invalid entries with a regular expression  array   array filter   w    filter   regexp

User · Answer

This one will only remove empty values and not falsey ones  which I think is more desirable   There is an option to also remove null values   This method should be much faster than using splice       function cleanArray a  removeNull            var i  l  temp               l   a length          if  removeNull                for  i   0  i  lt  l  i                      if  a i      undefined  amp  amp  a i      null                        temp push a i                                              else               for  i   0  i  lt  l  i                      if  a i      undefined                        temp push a i                                                      a length   0          l   temp length          for  i   0  i  lt  l  i                  a i    temp i                     temp length   0          return a            var myArray    1  2    3    3      0    null  false    NaN      4    4    5    6               cleanArray myArray       myArray

User · Answer

use filter to remove empty string in array    x000D   x000D  var s      1 201 karthikeyan K201 HELPER karthikeyan a limitlessmobil com 8248606269 7 14 2017 45680 TN-KAR24 8 800 1000 200 300 Karthikeyan 11 24 2017 Karthikeyan 11 24 2017 AVAILABLE r   x000D         x000D  var newArr   s filter function entry    return entry trim             x000D   x000D  console log newArr    x000D   x000D   x000D

User · Answer

Simply one liner    1  false      undefined  2  filter Boolean       1  2    or using underscorejs org     filter  1  false      undefined  2   Boolean       1  2     or even    compact  1  false      undefined  2        1  2

User · Answer

How about doing it this way       Removes all falsy values  arr   arr filter function array val       creates an anonymous filter func     var x   Boolean array val      checks if val is null     return x    true     returns val to array if not null

User · Answer

Try this   Pass it your array and it will return with empty elements removed    Updated to address the bug pointed out by Jason  function removeEmptyElem ary        for  var i   ary length - 1  i  gt   0  i--            if  ary i     undefined                 ary splice i  1                              return ary

User · Answer

If you ve got Javascript 1 6 or later you can use Array filter using a trivial return true callback function  e g    arr   arr filter function     return true        since  filter automatically skips missing elements in the original array   The MDN page linked above also contains a nice error-checking version of filter that can be used in JavaScript interpreters that don t support the official version   Note that this will not remove null entries nor entries with an explicit undefined value  but the OP specifically requested  missing  entries

User · Answer

You may find it easier to loop over your array and build a new array out of the items you want to keep from the array than by trying to loop and splice as has been suggested  since modifying the length of the array while it is being looped over can introduce problems   You could do something like this   function removeFalsyElementsFromArray someArray        var newArray           for var index   0  index  lt  someArray length  index              if someArray index                 newArray push someArray index                        return newArray      Actually here is a more generic solution   function removeElementsFromArray someArray  filter        var newArray           for var index   0  index  lt  someArray length  index              if filter someArray index      false                newArray push someArray index                        return newArray        then provide one or more filter functions that will     filter out the elements based on some condition  function isNullOrUndefined item        return  item    null    typeof item      undefined          then call the function like this  var myArray    1 2  3  3      4  4  5  6       var results   removeElementsFromArray myArray  isNullOrUndefined       results     1 2 3 3 4 4 5 6    You get the idea - you could then have other types of filter functions  Probably more than you need  but I was feeling generous

User · Answer

If you need to remove ALL empty values      null  undefined and 0     arr   arr filter function e  return e       To remove empty values and Line breaks   arr   arr filter function e   return e replace    r n  n  r  gm          Example   arr     hello  0    null undefined 1 100        arr filter function e  return e      Return     hello   1  100         UPDATE  based on Alnitak s comment   In some situations you may want to keep  0  in the array and remove anything else  null  undefined and      this is one way   arr filter function e   return e     0    e       Return     hello   0  1  100

User · Answer

What about this ES6    To remove Falsy value from an array   var arr    0 1 2  test   false  false true null 3 4 undefined 5  end     arr filter  v    gt      v   true       output      1  2   test    false   true  3  4  5   end

User · Answer

Since nobody else mentioned it and most people have underscore included in their project you can also use   without array   values        without   text    string   null  null  null   text    null       gt    text    string    text

User · Answer

ES6   let newArr   arr filter e   gt  e

User · Answer

You should use filter to get  array without empty elements  Example on ES6   const array    1  32  2  undefined  3   const newArray   array filter arr   gt  arr

User · Answer

With Underscore Lodash   General use case     without array  emptyVal  otherEmptyVal     without  1  2  1  0  3  1  4   0  1     With empties     without   foo    bar        baz            foobar         -- gt    foo    bar    baz    foobar     See lodash documentation for without

User · Answer

What about that   js gt   1 2  3  3   0   4  4  5  6      filter String  join      1 2 3 3 0 4 4 5 6

User · Answer

Filtering out invalid entries with a regular expression  array   array filter   w    filter   regexp

User · Answer

You should use filter to get  array without empty elements  Example on ES6   const array    1  32  2  undefined  3   const newArray   array filter arr   gt  arr

User · Answer

EDIT  This question was answered almost nine years ago when there were not many useful built-in methods in the Array prototype   Now  certainly  I would recommend you to use the filter method   Take in mind that this method will return you a new array with the elements that pass the criteria of the callback function you provide to it   For example  if you want to remove null or undefined values     x000D   x000D  var array    0  1  null  2      3  undefined  3       4   4   5   6       x000D   x000D  var filtered   array filter function  el    x000D    return el    null  x000D      x000D   x000D  console log filtered   x000D   x000D   x000D    It will depend on what you consider to be  empty  for example  if you were dealing with strings  the above function wouldn t remove elements that are an empty string   One typical pattern that I see often used is to remove elements that are falsy  which include an empty string     0  NaN  null  undefined  and false   You can pass to the filter method  the Boolean constructor function  or return the same element in the filter criteria function  for example   var filtered   array filter Boolean     Or  var filtered   array filter function el    return el        In both ways  this works because the filter method in the first case  calls the Boolean constructor as a function  converting the value  and in the second case  the filter method internally turns the return value of the callback implicitly to Boolean   If you are working with sparse arrays  and you are trying to get rid of the  holes   you can use the filter method passing a callback that returns true  for example    x000D   x000D  var sparseArray    0      1          2        3   x000D      cleanArray   sparseArray filter function      return true     x000D   x000D  console log cleanArray        0  1  2  3   x000D   x000D   x000D    Old answer  Don t do this   I use this method  extending the native Array prototype   Array prototype clean   function deleteValue      for  var i   0  i  lt  this length  i          if  this i     deleteValue                   this splice i  1         i--              return this      test   new Array      One    Two        Three        Four   clean      test2    1  2   3   3       4   4   5   6       test2 clean undefined     Or you can simply push the existing elements into other array      Will remove all falsy values  undefined  null  0  false  NaN and     empty string  function cleanArray actual      var newArray   new Array      for  var i   0  i  lt  actual length  i          if  actual i           newArray push actual i                return newArray     cleanArray  1  2   3   3       4   4   5   6

User · Answer

This works  I tested it in AppJet  you can copy-paste the code on its IDE and press  reload  to see it work  don t need to create an account      appjet version 0 1    function Joes remove someArray        var newArray           var element      for  element in someArray           if someArray element   undefined                 newArray push someArray element                        return newArray     var myArray2    1 2  3  3   0   4  4  5  6        print  Original array    myArray2   print  Clenased array    Joes remove myArray2        Returns   1 2 3 3 0 4 4 5 6

User · Answer

If you need to remove ALL empty values      null  undefined and 0     arr   arr filter function e  return e       To remove empty values and Line breaks   arr   arr filter function e   return e replace    r n  n  r  gm          Example   arr     hello  0    null undefined 1 100        arr filter function e  return e      Return     hello   1  100         UPDATE  based on Alnitak s comment   In some situations you may want to keep  0  in the array and remove anything else  null  undefined and      this is one way   arr filter function e   return e     0    e       Return     hello   0  1  100

User · Answer

Here is an example using variadic behavior  amp  ES2015 fat arrow expression   Array prototype clean   function       var args      slice call arguments     return this filter item   gt  args indexOf item      -1          Usage var arr        undefined  3   yes   undefined  undefined       arr clean undefined           3   yes        arr clean undefined           3   yes

User · Answer

var data         myAction  function array           return array filter function el              return  el      undefined    null                     join                 var string   data myAction   I    am       working        on       nodejs          console log string     Output       I am working on nodejs   It will remove empty element from array and display other element

User · Answer

Nice     very nice  We can also replace all array values like this  Array prototype ReplaceAllValues   function OldValue newValue        for  var i   0  i  lt  this length  i                     if  this i     OldValue                                this i    newValue

User · Answer

You can use filter with index and in operator  x000D   x000D  let a    1  2   3   let b   a filter  x i   gt  i in a    console log  a b    x000D   x000D   x000D

User · Answer

All the empty elements can be removed from an array by simply by using array filter String   It returns all non empty elements of an array in javascript

User · Answer

Nice     very nice  We can also replace all array values like this  Array prototype ReplaceAllValues   function OldValue newValue        for  var i   0  i  lt  this length  i                     if  this i     OldValue                                this i    newValue

User · Answer

Another way to do it is to take advantage of the length property of the array   pack the non-null items on the  left  of the array  then reduce the length   It is an in-place algorithm -does not allocates memory  too bad for the garbage collector-  and it has very good best average worst case behaviour   This solution  compared to others here  is between 2 to 50 times faster on Chrome  and 5 to 50 times faster on Firefox  as you might see here   http   jsperf com remove-null-items-from-array  The code below adds the non-enumerable  removeNull  method to the Array  which returns  this  for daisy-chaining     var removeNull   function         var nullCount   0                 var length      this length       for  var i 0  len this length  i lt len  i      if   this i    nullCount             no item is null     if   nullCount    return this         all items are null     if  nullCount    length    this length   0  return this          mix of null    non-null     var idest 0  isrc length-1      length -  nullCount                       while  true                find a non null  source  slot on the right          while   this isrc      isrc--  nullCount--              if      nullCount    break            break if found all null             find one null slot on the left  destination           while   this idest     idest                    perform copy          this idest  this isrc            if    --nullCount    break           idest     isrc --             this length length       return this        Object defineProperty Array prototype   removeNull                      value   removeNull  writable   true  configurable   true

User · Answer

What about this ES6    To remove Falsy value from an array   var arr    0 1 2  test   false  false true null 3 4 undefined 5  end     arr filter  v    gt      v   true       output      1  2   test    false   true  3  4  5   end

User · Answer

Removing all empty elements  If an array contains empty Objects  Arrays  and Strings alongside other empty elements  we can remove them with    x000D   x000D  const arr           not    empty          key   value     0  1  null  2       here        3  undefined  3            4    4    5    6        x000D   x000D  let filtered   JSON stringify  x000D    arr filter  obj    gt    x000D      return   null  undefined      includes obj  x000D       filter  el    gt    x000D      return typeof el     object     Object keys el  length  gt  0 x000D       x000D    x000D   x000D  console log JSON parse filtered   x000D   x000D   x000D    Simple compacting  removing empty elements from an array   With ES6    x000D   x000D  const arr    0  1  null  2      3  undefined  3            4    4    5    6         x000D   x000D  let filtered   arr filter  obj    gt    return   null  undefined  includes obj     x000D   x000D  console log filtered  x000D   x000D   x000D    With plain Javascript -    x000D   x000D  var arr    0  1  null  2      3  undefined  3            4    4    5    6         x000D   x000D  var filtered   arr filter function  obj    return   null  undefined  includes obj     x000D   x000D  console log filtered  x000D   x000D   x000D

User · Answer

var data         myAction  function array           return array filter function el              return  el      undefined    null                     join                 var string   data myAction   I    am       working        on       nodejs          console log string     Output       I am working on nodejs   It will remove empty element from array and display other element

User · Answer

All the empty elements can be removed from an array by simply by using array filter String   It returns all non empty elements of an array in javascript

User · Answer

This works  I tested it in AppJet  you can copy-paste the code on its IDE and press  reload  to see it work  don t need to create an account      appjet version 0 1    function Joes remove someArray        var newArray           var element      for  element in someArray           if someArray element   undefined                 newArray push someArray element                        return newArray     var myArray2    1 2  3  3   0   4  4  5  6        print  Original array    myArray2   print  Clenased array    Joes remove myArray2        Returns   1 2 3 3 0 4 4 5 6

User · Answer

If using a library is an option I know underscore js has a function called compact   http   documentcloud github com underscore  it also has several other useful functions related to arrays and collections   Here is an excerpt from their documentation        compact array         Returns a copy of the array with all falsy values removed  In JavaScript  false  null  0      undefined and NaN are all falsy         compact  0  1  false  2      3             1  2  3

User · Answer

The best way to remove empty elements  is to use Array prototype filter    as already mentioned in other answers   Unfortunately  Array prototype filter   is not supported by IE lt 9  If you still need to support IE8 or an even older version of IE  you could use the following polyfill to add support for Array prototype filter   in these browsers    if   Array prototype filter      Array prototype filter   function fun    thisArg           use strict       if  this     void 0    this     null          throw new TypeError              var t   Object this       var len   t length  gt  gt  gt  0      if  typeof fun      function           throw new TypeError              var res           var thisArg   arguments length  gt   2   arguments 1    void 0      for  var i   0  i  lt  len  i            if  i in t            var val   t i           if  fun call thisArg  val  i  t               res push val                               return res

User · Answer

EDIT  This question was answered almost nine years ago when there were not many useful built-in methods in the Array prototype   Now  certainly  I would recommend you to use the filter method   Take in mind that this method will return you a new array with the elements that pass the criteria of the callback function you provide to it   For example  if you want to remove null or undefined values     x000D   x000D  var array    0  1  null  2      3  undefined  3       4   4   5   6       x000D   x000D  var filtered   array filter function  el    x000D    return el    null  x000D      x000D   x000D  console log filtered   x000D   x000D   x000D    It will depend on what you consider to be  empty  for example  if you were dealing with strings  the above function wouldn t remove elements that are an empty string   One typical pattern that I see often used is to remove elements that are falsy  which include an empty string     0  NaN  null  undefined  and false   You can pass to the filter method  the Boolean constructor function  or return the same element in the filter criteria function  for example   var filtered   array filter Boolean     Or  var filtered   array filter function el    return el        In both ways  this works because the filter method in the first case  calls the Boolean constructor as a function  converting the value  and in the second case  the filter method internally turns the return value of the callback implicitly to Boolean   If you are working with sparse arrays  and you are trying to get rid of the  holes   you can use the filter method passing a callback that returns true  for example    x000D   x000D  var sparseArray    0      1          2        3   x000D      cleanArray   sparseArray filter function      return true     x000D   x000D  console log cleanArray        0  1  2  3   x000D   x000D   x000D    Old answer  Don t do this   I use this method  extending the native Array prototype   Array prototype clean   function deleteValue      for  var i   0  i  lt  this length  i          if  this i     deleteValue                   this splice i  1         i--              return this      test   new Array      One    Two        Three        Four   clean      test2    1  2   3   3       4   4   5   6       test2 clean undefined     Or you can simply push the existing elements into other array      Will remove all falsy values  undefined  null  0  false  NaN and     empty string  function cleanArray actual      var newArray   new Array      for  var i   0  i  lt  actual length  i          if  actual i           newArray push actual i                return newArray     cleanArray  1  2   3   3       4   4   5   6

User · Answer

Try this   Pass it your array and it will return with empty elements removed    Updated to address the bug pointed out by Jason  function removeEmptyElem ary        for  var i   ary length - 1  i  gt   0  i--            if  ary i     undefined                 ary splice i  1                              return ary

[javascript] Remove empty elements from an array in Javascript

Examples related to javascript

Examples related to arrays