Check if an array contains any element of another array in JavaScript

Question

I have a target array   apple   banana   orange    and I want to check if other arrays contain any one of the target array elements    For example      apple   grape     returns true     apple   banana   pineapple     returns true     grape    pineapple     returns false    How can I do it in JavaScript

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Personally  I would use the following function   var arrayContains   function array  toMatch        var arrayAsString   array toString        return  arrayAsString indexOf     toMatch       gt -1       The  toString    method will always use commas to separate the values  Will only really work with primitive types

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Just one more solution  var a1    1  2  3  4  5  var a2    2  4    Check if a1 contain all element of a2  var result   a1 filter e   gt  a2 indexOf e      -1  length     a2 length console log result

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Using filter indexOf    x000D   x000D  function containsAny source target  x000D    x000D      var result   source filter function item   return target indexOf item   gt  -1       x000D      return  result length  gt  0     x000D        x000D   x000D   x000D    results x000D   x000D  var fruits     apple   banana   orange    x000D   x000D   x000D  console log containsAny fruits   apple   grape      x000D   x000D  console log containsAny fruits   apple   banana   pineapple      x000D   x000D  console log containsAny fruits   grape    pineapple      x000D   x000D   x000D

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I wrote 3 solutions  Essentially they do the same  They return true as soon as they get true  I wrote the 3 solutions just for showing 3 different way to do things  Now  it depends what you like more  You can use performance now   to check the performance of one solution or the other  In my solutions I m also checking which array is the biggest and which one is the smallest to make the operations more efficient   The 3rd solution may not be the cutest but is efficient  I decided to add it because in some coding interviews you are not allowed to use built-in methods   Lastly  sure   we can come up with a solution with 2 NESTED for loops  the brute force way  but you want to avoid that because the time complexity is bad O n 2    Note       instead of using  includes   like some other people did  you can use    indexOf    if you do just check if the value is bigger than 0  If   the value doesn t exist will give you -1  if it does exist  it will give you   greater than 0    indexOf   vs includes    Which one has better performance  indexOf   for a little bit  but includes is more readable in my opinion   If I m not mistaken  includes   and indexOf   use loops behind the scene  so you will be at O n 2  when using them with  some     USING loop    const compareArraysWithIncludes    arr1  arr2    gt         const  smallArray  bigArray            arr1 length  lt  arr2 length    arr1  arr2     arr2  arr1         for  let i   0  i  lt  smallArray length  i             return bigArray includes smallArray i                  return false           USING  some     const compareArraysWithSome    arr1  arr2    gt      const  smallArray  bigArray        arr1 length  lt  arr2 length    arr1  arr2     arr2  arr1     return smallArray some c   gt  bigArray includes c         USING MAPS Time complexity O 2n   O n   const compararArraysUsingObjs    arr1  arr2    gt      const map          const  smallArray  bigArray        arr1 length  lt  arr2 length    arr1  arr2     arr2  arr1      for  let i   0  i  lt  smallArray length  i          if   map smallArray i            map smallArray i     true               for  let i   0  i  lt  bigArray length  i          if  map bigArray i            return true               return false       Code in my  stackblitz  I m not an expert in performance nor BigO so if something that I said is wrong let me know

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I found this short and sweet syntax to match all or some elements between two arrays  For example     OR operation  find if any of array2 elements exists in array1  This will return as soon as there is a first match as some method breaks when function returns TRUE  let array1     a    b    c    d    e    array2     a    b     console log array2 some ele   gt  array1 includes ele          prints TRUE     AND operation  find if all of array2 elements exists in array1  This will return as soon as there is a no first match as some method breaks when function returns TRUE  let array1     a    b    c    d    e    array2     a    x     console log  array2 some ele   gt   array1 includes ele          prints FALSE  Hope that helps someone in future

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What about using a combination of some findIndex and indexOf   So something like this   var array1     apple   banana   orange    var array2     grape    pineapple     var found   array1 some function v    return array2 indexOf v     -1        To make it more readable you could add this functionality to the Array object itself   Array prototype indexOfAny   function  array        return this findIndex function v    return array indexOf v     -1         Array prototype containsAny   function  array        return this indexOfAny array     -1      Note  If you d want to do something with a predicate you could replace the inner indexOf with another findIndex and a predicate

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const areCommonElements    arr1  arr2    gt        const arr2Set   new Set arr2       return arr1 some el   gt  arr2Set has el         Or you can even have a better performance if you first find out which of these two arrays is longer and making Set out for the longest array  while applying some method on the shortest one   const areCommonElements    arr1  arr2    gt        const  shortArr  longArr     arr1 length  lt  arr2 length     arr1  arr2     arr2  arr1       const longArrSet   new Set longArr       return shortArr some el   gt  longArrSet has el

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vanilla js         description determine if an array contains one or more items from another array      param  array  haystack the array to search      param  array  arr the array providing items to check for in the haystack      return  boolean  true false if haystack contains at least one item from arr      var findOne   function  haystack  arr        return arr some function  v            return haystack indexOf v   gt   0              As noted by  loganfsmyth you can shorten it in ES2016 to         description determine if an array contains one or more items from another array      param  array  haystack the array to search      param  array  arr the array providing items to check for in the haystack      return  boolean  true false if haystack contains at least one item from arr      var findOne    haystack  arr    gt        return arr some v   gt  haystack includes v        or simply as arr some v   gt  haystack includes v

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Not sure how efficient this might be in terms of performance  but this is what I use using array destructuring to keep everything nice and short  const shareElements    arr1  arr2    gt      const typeArr       arr1     arr2    const typeSet   new Set typeArr    return typeArr length  gt  typeSet size    Since sets cannot have duplicate elements while arrays can  combining both input arrays  converting it to a set  and comparing the set size and array length would tell you if they share any elements

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I came up with a solution in node using underscore js like this   var checkRole     intersection   A   B      A   B   C     if    isEmpty checkRole           next

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Array  filter   with a nested call to  find   will return all elements in the first array that are members of the second array  Check the length of the returned array to determine if any of the second array were in the first array   getCommonItems firstArray  secondArray      return firstArray filter  firstArrayItem    gt        return secondArray find  secondArrayItem    gt          return firstArrayItem     secondArrayItem

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You could use lodash and do     intersection originalTarget  arrayToCheck  length  gt  0   Set intersection is done on both collections producing an array of identical elements

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It can be done by simply iterating across the main array and check whether other array contains any of the target element or not   Try this   function Check A        var myarr     apple    banana    orange        var i  j      var totalmatches   0      for  i   0  i  lt  myarr length  i              for  j   0  j  lt  A length    j                if  myarr i     A j                      totalmatches                                        if  totalmatches  gt  0            return true        else           return false          var fruits1   new Array  apple    grape    alert Check fruits1     var fruits2   new Array  apple    banana    pineapple    alert Check fruits2     var fruits3   new Array  grape    pineapple    alert Check fruits3      DEMO at JSFIDDLE

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console log  searching Array    finding array   console log  searching in   reference array   var check match counter   0  for  var j   finding array length - 1  j  gt   0  j--         if reference array indexOf finding array j    gt  0                check match counter   check match counter   1           var match    check match counter  gt  0    true   false  console log  Final result   match

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If you don t need type coercion  because of the use of indexOf   you could try something like the following   var arr    1  2  3   var check    3  4    var found   false  for  var i   0  i  lt  check length  i          if  arr indexOf check i    gt  -1            found   true          break          console log found     Where arr contains the target items  At the end  found will show if the second array had at least one match against the target   Of course  you can swap out numbers for anything you want to use - strings are fine  like your example   And in my specific example  the result should be true because the second array s 3 exists in the target     UPDATE   Here s how I d organize it into a function  with some minor changes from before    var anyMatchInArray    function           use strict        var targetArray  func       targetArray     apple    banana    orange        func   function  checkerArray            var found   false          for  var i   0  j   checkerArray length   found  amp  amp  i  lt  j  i                  if  targetArray indexOf checkerArray i    gt  -1                    found   true                                  return found              return func          DEMO  http   jsfiddle net u8Bzt   In this case  the function could be modified to have targetArray be passed in as an argument instead of hardcoded in the closure     UPDATE2   While my solution above may work and be  hopefully more  readable  I believe the  better  way to handle the concept I described is to do something a little differently  The  problem  with the above solution is that the indexOf inside the loop causes the target array to be looped over completely for every item in the other array  This can easily be  fixed  by using a  lookup   a map   a JavaScript object literal   This allows two simple loops  over each array  Here s an example   var anyMatchInArray   function  target  toMatch         use strict        var found  targetMap  i  j  cur       found   false      targetMap               Put all values in the  target  array into a map  where         the keys are the values from the array     for  i   0  j   target length  i  lt  j  i              cur   target i           targetMap cur    true                Loop over all items in the  toMatch  array and see if any of         their values are in the map from before     for  i   0  j   toMatch length   found  amp  amp   i  lt  j   i              cur   toMatch i           found     targetMap cur              If found   targetMap cur   will return true  otherwise it             will return  undefined    that s what the      is for            return found       DEMO  http   jsfiddle net 5Lv9v   The downside to this solution is that only numbers and strings  and booleans  can be used  correctly   because the values are  implicitly  converted to strings and set as the keys to the lookup map  This isn t exactly good possible easily done for non-literal values

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When I looked at your answers  I could not find the answer I wanted  I did something myself and I want to share this with you  It will be true only if the words entered  array  are correct   x000D   x000D  function contains a b        let counter   0      for var i   0  i  lt  b length  i               if a includes b i    counter              if counter     b length  return true      return false     let main array     foo   bar   baz    let sub array a     foo   foobar    let sub array b     foo   bar     console log contains main array  sub array a       returns false console log contains main array sub array b        returns true x000D   x000D   x000D

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You can use a nested Array prototype some call  This has the benefit that it will bail at the first match instead of other solutions that will run through the full nested loop   eg   var arr    1  2  3   var match    2  4    var hasMatch   arr some a   gt  match some m   gt  a     m

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My solution applies Array prototype some   and Array prototype includes   array helpers which do their job pretty efficient as well  ES6  x000D   x000D  const originalFruits     apple   banana   orange    x000D   x000D  const fruits1     apple   banana   pineapple    x000D   x000D  const fruits2     grape    pineapple    x000D   x000D  const commonFruits    myFruitsArr  otherFruitsArr    gt    x000D    return myFruitsArr some fruit   gt  otherFruitsArr includes fruit   x000D    x000D  console log commonFruits originalFruits  fruits1     returns true  x000D  console log commonFruits originalFruits  fruits2     returns false  x000D   x000D   x000D

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Adding to Array Prototype Disclaimer  Many would strongly advise against this  The only time it d really be a problem was if a library added a prototype function with the same name  that behaved differently  or something like that  Code  Array prototype containsAny   function arr        return this some           v    gt   arr indexOf v   gt   0           Without using big arrow functions  Array prototype containsAny   function arr        return this some function  v            return arr indexOf v   gt   0           Usage var a     quot a quot   quot b quot    console log a containsAny   quot b quot   quot z quot           Outputs true  console log a containsAny   quot z quot           Outputs false

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If you re not opposed to using a libray  http   underscorejs org  has an intersection method  which can simplify this   var     require  underscore     var target      apple    orange    banana    var fruit2      apple    orange    mango    var fruit3      mango    lemon    pineapple    var fruit4      orange    lemon    grapes     console log   intersection target  fruit2      returns  apple  orange  console log   intersection target  fruit3      returns    console log   intersection target  fruit4      returns  orange    The intersection function will return a new array with the items that it matched and if not matches it returns empty array

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Here is an interesting case I thought I should share   Let s say that you have an array of objects and an array of selected filters   let arr         id   x   tags    foo          id   y   tags    foo    bar          id   z   tags    baz         const filters     foo      To apply the selected filters to this structure we can  if  filters length  gt  0    arr   arr filter obj   gt      obj tags some tag   gt  filters includes tag                     id   x   tags    foo             id   y   tags    foo    bar

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Update  Paul Grimshaw answer  use includes insteed of indexOf for more readable     let found   arr1 some r   arr2 indexOf r     0    let found   arr1 some r   arr2 includes r

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ES6 solution   let arr1    1  2  3   let arr2    2  3    let isFounded   arr1 some  ai   gt  arr2 includes ai       Unlike of it  Must contains all values   let allFounded   arr2 every  ai   gt  arr1 includes ai       Hope  will be helpful

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Vanilla JS with partial matching  amp  case insensitive  The problem with some previous approaches is that they require an exact match of every word  But  What if you want to provide results for partial matches   function search arrayToSearch  wordsToSearch        arrayToSearch filter v   gt           wordsToSearch every w   gt               v toLowerCase   split                       reduce  isIn  h    gt  isIn    String h  indexOf w   gt   0  false                              Usage var myArray     Attach tag    Attaching tags    Blah blah blah    var searchText    Tag attach   var searchArr   searchText toLowerCase   split           tag    attach    var matches   search myArray  searchArr     Will return     Attach tag    Attaching tags     This is useful when you want to provide a search box where users type words and the results can have those words in any order  position and case

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Vanilla JS  ES2016   const found   arr1 some r  gt  arr2 includes r     ES6   const found   arr1 some r  gt  arr2 indexOf r   gt   0    How it works  some     checks each element of the array against a test function and returns true if any element of the array passes the test function  otherwise  it returns false  indexOf      gt   0 and includes     both return true if the given argument is present in the array

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var target     apple   banana   orange    var checkArray     apple   banana   pineapple     var containsOneCommonItem   target some x   gt  checkArray some y   gt  y     x        apple   grape     returns true     apple   banana   pineapple     returns true     grape    pineapple     returns false

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With underscorejs  var a1    1 2 3   var a2    1 2      every a1  function e   return   include a2  e            gt  false   every a2  function e   return   include a1  e            gt  true

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ES6  fastest   const a     a    b    c    const b     c    a    d    a some v  gt  b indexOf v      -1    ES2016  const a     a    b    c    const b     c    a    d    a some v   gt  b includes v      Underscore  const a     a    b    c    const b     c    a    d      intersection a  b    DEMO  https   jsfiddle net r257wuv5   jsPerf  https   jsperf com array-contains-any-element-of-another-array

[javascript] Check if an array contains any element of another array in JavaScript

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