How to append something to an array

Question

How do I append an object  such as a string or number  to an array in JavaScript

User · Answer

If you want to append a single value into an array, simply use the push method. It will add a new element at the end of the array.

But if you intend to add multiple elements then store the elements in a new array and concat the second array with the first array...either way you wish.

arr=['a','b','c'];
arr.push('d');
//now print the array in console.log and it will contain 'a','b','c','d' as elements.
console.log(array);

User · Answer

You can use push and apply function to append two arrays    x000D   x000D  var array1    11  32  75   x000D  var array2    99  67  34   x000D   x000D  Array prototype push apply array1  array2   x000D  console log array1   x000D   x000D   x000D    It will append array2 to array1  Now array1 contains  11  32  75  99  67  34   This code is much simpler than writing for loops to copy each and every items in the array

User · Answer

Let the array length property do the work   myarray myarray length     new element value added to the end of the array     myarray length returns the number of strings in the array  JS is zero based so the next element key of the array will be the current length of the array  EX   var myarray    0  1  2  3       myarrayLength   myarray length    myarrayLength is set to 4

User · Answer

There are a couple of ways to append an array in JavaScript   1  The push   method adds one or more elements to the end of an array and returns the new length of the array   var a    1  2  3   a push 4  5   console log a     Output    1  2  3  4  5    2  The unshift   method adds one or more elements to the beginning of an array and returns the new length of the array   var a    1  2  3   a unshift 4  5   console log a      Output    4  5  1  2  3    3  The concat   method is used to merge two or more arrays  This method does not change the existing arrays  but instead returns a new array   var arr1     a    b    c    var arr2     d    e    f    var arr3   arr1 concat arr2   console log arr3     Output      a    b    c    d    e    f      4  You can use the array s  length property to add an element to the end of the array   var ar     one    two    three    ar ar length     four   console log  ar       Output      one    two    three    four     5  The splice   method changes the content of an array by removing existing elements and or adding new elements   var myFish     angel    clown    mandarin    surgeon    myFish splice 4  0   nemo      array splice start  deleteCount  item1  item2       console log myFish     Output     angel    clown    mandarin    surgeon   nemo     6  You can also add a new element to an array simply by specifying a new index and assigning a value   var ar     one    two    three    ar 3     four      add new element to ar console log ar     Output     one    two   three   four

User · Answer

Some quick benchmarking  each test   500k appended elements and the results are averages of multiple runs  showed the following   Firefox 3 6  Mac     Small arrays  arr arr length    b is faster  300ms vs  800ms  Large arrays  arr push b  is faster  500ms vs  900ms    Safari 5 0  Mac     Small arrays  arr arr length    b is faster  90ms vs  115ms  Large arrays  arr arr length    b is faster  160ms vs  185ms    Google Chrome 6 0  Mac     Small arrays  No significant difference  and Chrome is FAST  Only  38ms     Large arrays  No significant difference  160ms    I like the arr push   syntax better  but I think I d be better off with the arr arr length  Version  at least in raw speed  I d love to see the results of an IE run though     My benchmarking loops   function arrpush small         var arr1           for  a   0  a  lt  100  a                  arr1               for  i   0  i  lt  5000  i                          arr1 push  elem    i                      function arrlen small         var arr2           for  b   0  b  lt  100  b                  arr2               for  j   0  j  lt  5000  j                          arr2 arr2 length     elem    j                      function arrpush large         var arr1           for  i   0  i  lt  500000  i                  arr1 push  elem    i            function arrlen large         var arr2           for  j   0  j  lt  500000  j                  arr2 arr2 length     elem    j

User · Answer

push   adds a new element to the end of an array  pop   removes an element from the end of an array   To append an object  such as a string or number  to an array use - array push toAppend

User · Answer

Now  you can take advantage of ES6 syntax and just do   let array    1  2   console log     array  3      keeping the original array immutable

User · Answer

Use the Array prototype push method to append values to the end of an array   x000D   x000D     initialize array var arr        Hi      Hello      Bonjour         append new value to the array arr push  Hola     console log arr   x000D   x000D   x000D    You can use the push   function to append more than one value to an array in a single call   x000D   x000D     initialize array var arr     Hi    Hello    Bonjour    Hola        append multiple values to the array arr push  Salut    Hey        display all values for  var i   0  i  lt  arr length  i        console log arr i      x000D   x000D   x000D    Update If you want to add the items of one array to another array  you can use firstArray concat secondArray    x000D   x000D  var arr        apple      banana      cherry      arr   arr concat      dragonfruit      elderberry      fig       console log arr   x000D   x000D   x000D   Update Just an addition to this answer if you want to prepend any value to the start of an array  i e  first index  then you can use Array prototype unshift for this purpose   x000D   x000D  var arr    1  2  3   arr unshift 0   console log arr   x000D   x000D   x000D   It also supports appending multiple values at once just like push   Update Another way with ES6 syntax is to return a new array with the spread syntax  This leaves the original array unchanged  but returns a new array with new items appended  compliant with the spirit of functional programming   x000D   x000D  const arr        Hi      Hello      Bonjour       const newArr          arr     Salut       console log newArr   x000D   x000D   x000D

User · Answer

Some quick benchmarking  each test   500k appended elements and the results are averages of multiple runs  showed the following   Firefox 3 6  Mac     Small arrays  arr arr length    b is faster  300ms vs  800ms  Large arrays  arr push b  is faster  500ms vs  900ms    Safari 5 0  Mac     Small arrays  arr arr length    b is faster  90ms vs  115ms  Large arrays  arr arr length    b is faster  160ms vs  185ms    Google Chrome 6 0  Mac     Small arrays  No significant difference  and Chrome is FAST  Only  38ms     Large arrays  No significant difference  160ms    I like the arr push   syntax better  but I think I d be better off with the arr arr length  Version  at least in raw speed  I d love to see the results of an IE run though     My benchmarking loops   function arrpush small         var arr1           for  a   0  a  lt  100  a                  arr1               for  i   0  i  lt  5000  i                          arr1 push  elem    i                      function arrlen small         var arr2           for  b   0  b  lt  100  b                  arr2               for  j   0  j  lt  5000  j                          arr2 arr2 length     elem    j                      function arrpush large         var arr1           for  i   0  i  lt  500000  i                  arr1 push  elem    i            function arrlen large         var arr2           for  j   0  j  lt  500000  j                  arr2 arr2 length     elem    j

User · Answer

Use concat    x000D   x000D  a    1  2  3   x000D  b    3  4  5   x000D  a   a concat b   x000D  console log a   x000D   x000D   x000D

User · Answer

Append Single Element    Append to the end arrName push  newName1       Prepend to the start arrName unshift  newName1       Insert at index 1 arrName splice 1  0  newName1      1  index number  0  number of element to remove  newName1  new element      Replace index 3  of exists   add new element otherwise  arrName 3     newName1     Append Multiple Elements    Insert from index number 1 arrName splice 1  0  newElemenet1    newElemenet2    newElemenet3      1  index number from where insert starts     0  number of element to remove     newElemenet1 2 3  new elements   Append array    join two or more arrays arrName concat newAry1  newAry2     newAry1 newAry2  Two different arrays which are to be combined  concatenated  to an existing array

User · Answer

push   adds a new element to the end of an array  pop   removes an element from the end of an array   To append an object  such as a string or number  to an array use - array push toAppend

User · Answer

you can do it using new javascript Es 6 feature       initialize array  var arr          Hi        Hello        Bangladesh         append new value to the array  arr      arr    Feni        or you can put a variable value  var testValue    Cool    arr       arr   testValue     console log arr        final output     Hi    Hello    Bangladesh    Feni    Cool

User · Answer

Use the Array prototype push method to append values to the end of an array   x000D   x000D     initialize array var arr        Hi      Hello      Bonjour         append new value to the array arr push  Hola     console log arr   x000D   x000D   x000D    You can use the push   function to append more than one value to an array in a single call   x000D   x000D     initialize array var arr     Hi    Hello    Bonjour    Hola        append multiple values to the array arr push  Salut    Hey        display all values for  var i   0  i  lt  arr length  i        console log arr i      x000D   x000D   x000D    Update If you want to add the items of one array to another array  you can use firstArray concat secondArray    x000D   x000D  var arr        apple      banana      cherry      arr   arr concat      dragonfruit      elderberry      fig       console log arr   x000D   x000D   x000D   Update Just an addition to this answer if you want to prepend any value to the start of an array  i e  first index  then you can use Array prototype unshift for this purpose   x000D   x000D  var arr    1  2  3   arr unshift 0   console log arr   x000D   x000D   x000D   It also supports appending multiple values at once just like push   Update Another way with ES6 syntax is to return a new array with the spread syntax  This leaves the original array unchanged  but returns a new array with new items appended  compliant with the spirit of functional programming   x000D   x000D  const arr        Hi      Hello      Bonjour       const newArr          arr     Salut       console log newArr   x000D   x000D   x000D

User · Answer

You can use the push   if you want to add values e g  arr push  Test1    Test2     If you have array you can use concat   e g  Array1 concat Array2   If you have just one element to add you can also try length menthod e g  array aray length     test

User · Answer

There are a couple of ways to append an array in JavaScript   1  The push   method adds one or more elements to the end of an array and returns the new length of the array   var a    1  2  3   a push 4  5   console log a     Output    1  2  3  4  5    2  The unshift   method adds one or more elements to the beginning of an array and returns the new length of the array   var a    1  2  3   a unshift 4  5   console log a      Output    4  5  1  2  3    3  The concat   method is used to merge two or more arrays  This method does not change the existing arrays  but instead returns a new array   var arr1     a    b    c    var arr2     d    e    f    var arr3   arr1 concat arr2   console log arr3     Output      a    b    c    d    e    f      4  You can use the array s  length property to add an element to the end of the array   var ar     one    two    three    ar ar length     four   console log  ar       Output      one    two    three    four     5  The splice   method changes the content of an array by removing existing elements and or adding new elements   var myFish     angel    clown    mandarin    surgeon    myFish splice 4  0   nemo      array splice start  deleteCount  item1  item2       console log myFish     Output     angel    clown    mandarin    surgeon   nemo     6  You can also add a new element to an array simply by specifying a new index and assigning a value   var ar     one    two    three    ar 3     four      add new element to ar console log ar     Output     one    two   three   four

User · Answer

Now  you can take advantage of ES6 syntax and just do   let array    1  2   console log     array  3      keeping the original array immutable

User · Answer

Use concat    x000D   x000D  a    1  2  3   x000D  b    3  4  5   x000D  a   a concat b   x000D  console log a   x000D   x000D   x000D

User · Answer

Let the array length property do the work   myarray myarray length     new element value added to the end of the array     myarray length returns the number of strings in the array  JS is zero based so the next element key of the array will be the current length of the array  EX   var myarray    0  1  2  3       myarrayLength   myarray length    myarrayLength is set to 4

User · Answer

Append a value to an array  Since Array prototype push adds one or more elements to the end of an array and returns the new length of the array  sometimes we want just to get the new up-to-date array so we can do something like so   const arr    1  2  3   const val   4   arr concat  val        1  2  3  4    Or just       arr  val      1  2  3  4

User · Answer

You can use push method   Array prototype append   function destArray        destArray   destArray             this push call this    destArray        return this    var arr    1 2 5 67   var arr1    7 4 7 8   console log arr append arr1       7  4  7  8  1  4  5  67  7  console log arr append  Hola      1  2  5  67  7  4  7  8   H    o    l    a

User · Answer

The push   method adds new items to the end of an array  and returns the new length  Example   var fruits     Banana    Orange    Apple    Mango    fruits push  Kiwi        The result of fruits will be  Banana  Orange  Apple  Mango  Kiwi   The exact answer to your question is already answered  but let s look at some other ways to add items to an array   The unshift   method adds new items to the beginning of an array  and returns the new length  Example   var fruits     Banana    Orange    Apple    Mango    fruits unshift  Lemon    Pineapple        The result of fruits will be  Lemon  Pineapple  Banana  Orange  Apple  Mango   And lastly  the concat   method is used to join two or more arrays  Example   var fruits     Banana    Orange    var moreFruits     Apple    Mango    Lemon    var allFruits   fruits concat moreFruits       The values of the children array will be  Banana  Orange  Apple  Mango  Lemon

User · Answer

Just want to add a snippet for non-destructive addition of an element    var newArr   oldArr concat  newEl

User · Answer

With the new ES6 spread operator  joining two arrays using push becomes even easier    x000D   x000D  var arr    1  2  3  4  5   x000D  var arr2    6  7  8  9  10   x000D  arr push    arr2   x000D  console log arr   x000D   x000D   x000D    This adds the contents of arr2 onto the end of arr   Babel REPL Example

User · Answer

You  push   that value in   Example  array push value

User · Answer

Append a single item  To append a single item to an array  use the push   method provided by the Array object   const fruits     banana    pear    apple   fruits push  mango   console log fruits    push   mutates the original array   To create a new array instead  use the concat   Array method   const fruits     banana    pear    apple   const allfruits   fruits concat  mango   console log allfruits    Notice that concat   does not actually add an item to the array  but creates a new array  which you can assign to another variable  or reassign to the original array  declaring it as let  as you cannot reassign a const    const fruits     banana    pear    apple   const allfruits   fruits concat  mango   console log allfruits    let fruits     banana    pear    apple   fruits   fruits concat  mango     Append multiple items  To append a multiple item to an array  you can use push   by calling it with multiple arguments   const fruits     banana    pear    apple   fruits push  mango    melon    avocado   console log fruits    You can also use the concat   method you saw before  passing a list of items separated by a comma   const fruits     banana    pear    apple   const allfruits   fruits concat  mango    melon    avocado   console log allfruits    or an array   const fruits     banana    pear    apple   const allfruits   fruits concat   mango    melon    avocado    console log allfruits    Remember that as described previously this method does not mutate the original array  but it  returns a new array      Originally posted at

User · Answer

Append a value to an array  Since Array prototype push adds one or more elements to the end of an array and returns the new length of the array  sometimes we want just to get the new up-to-date array so we can do something like so   const arr    1  2  3   const val   4   arr concat  val        1  2  3  4    Or just       arr  val      1  2  3  4

User · Answer

If you re only appending a single variable  then push   works just fine  If you need to append another array  use concat      x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  var ar3   ar1 concat ar2   x000D   x000D  alert ar1   x000D  alert ar2   x000D  alert ar3   x000D   x000D   x000D    The concat does not affect ar1 and ar2 unless reassigned  for example    x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  ar1   ar1 concat ar2   x000D  alert ar1   x000D   x000D   x000D    Lots of great info here

User · Answer

If you know the highest index  such as stored in a variable  i   then you can do  myArray i   1    someValue    However if you don t know then you can either use   myArray push someValue     as other answers suggested  or you can use  myArray myArray length    someValue     Note that the array is zero based so  length return the highest index plus one   Also note that you don t have to add in order and you can actually skip values  as in  myArray myArray length   1000    someValue    In which case the values in between will have a value of undefined   It is therefore a good practice when looping through a JavaScript to verify that a value actually exists at that point   This can be done by something like the following   if myArray i       undefined    continue      if you are certain that you don t have any zeros in the array then you can just do   if  myArray i    continue      Of course make sure in this case that you don t use as the condition myArray i   as some people over the internet suggest based on the end that as soon as i is greater then the highest index it will return undefined which evaluates to false

User · Answer

If you re only appending a single variable  then push   works just fine  If you need to append another array  use concat      x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  var ar3   ar1 concat ar2   x000D   x000D  alert ar1   x000D  alert ar2   x000D  alert ar3   x000D   x000D   x000D    The concat does not affect ar1 and ar2 unless reassigned  for example    x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  ar1   ar1 concat ar2   x000D  alert ar1   x000D   x000D   x000D    Lots of great info here

User · Answer

If arr is an array  and val is the value you wish to add use   arr push val     E g    x000D   x000D  var arr     a    b    c    x000D  arr push  d    x000D  console log arr   x000D   x000D   x000D

User · Answer

Use the Array prototype push method to append values to the end of an array   x000D   x000D     initialize array var arr        Hi      Hello      Bonjour         append new value to the array arr push  Hola     console log arr   x000D   x000D   x000D    You can use the push   function to append more than one value to an array in a single call   x000D   x000D     initialize array var arr     Hi    Hello    Bonjour    Hola        append multiple values to the array arr push  Salut    Hey        display all values for  var i   0  i  lt  arr length  i        console log arr i      x000D   x000D   x000D    Update If you want to add the items of one array to another array  you can use firstArray concat secondArray    x000D   x000D  var arr        apple      banana      cherry      arr   arr concat      dragonfruit      elderberry      fig       console log arr   x000D   x000D   x000D   Update Just an addition to this answer if you want to prepend any value to the start of an array  i e  first index  then you can use Array prototype unshift for this purpose   x000D   x000D  var arr    1  2  3   arr unshift 0   console log arr   x000D   x000D   x000D   It also supports appending multiple values at once just like push   Update Another way with ES6 syntax is to return a new array with the spread syntax  This leaves the original array unchanged  but returns a new array with new items appended  compliant with the spirit of functional programming   x000D   x000D  const arr        Hi      Hello      Bonjour       const newArr          arr     Salut       console log newArr   x000D   x000D   x000D

User · Answer

Use the Array prototype push method to append values to the end of an array   x000D   x000D     initialize array var arr        Hi      Hello      Bonjour         append new value to the array arr push  Hola     console log arr   x000D   x000D   x000D    You can use the push   function to append more than one value to an array in a single call   x000D   x000D     initialize array var arr     Hi    Hello    Bonjour    Hola        append multiple values to the array arr push  Salut    Hey        display all values for  var i   0  i  lt  arr length  i        console log arr i      x000D   x000D   x000D    Update If you want to add the items of one array to another array  you can use firstArray concat secondArray    x000D   x000D  var arr        apple      banana      cherry      arr   arr concat      dragonfruit      elderberry      fig       console log arr   x000D   x000D   x000D   Update Just an addition to this answer if you want to prepend any value to the start of an array  i e  first index  then you can use Array prototype unshift for this purpose   x000D   x000D  var arr    1  2  3   arr unshift 0   console log arr   x000D   x000D   x000D   It also supports appending multiple values at once just like push   Update Another way with ES6 syntax is to return a new array with the spread syntax  This leaves the original array unchanged  but returns a new array with new items appended  compliant with the spirit of functional programming   x000D   x000D  const arr        Hi      Hello      Bonjour       const newArr          arr     Salut       console log newArr   x000D   x000D   x000D

User · Answer

If arr is an array  and val is the value you wish to add use   arr push val     E g    x000D   x000D  var arr     a    b    c    x000D  arr push  d    x000D  console log arr   x000D   x000D   x000D

User · Answer

If you want to append two arrays -  var a     a    b    var b     c    d      then you could use   var c   a concat b     And if you want to add record g to array   var a     then you could use   a push  g

User · Answer

You  push   that value in   Example  array push value

User · Answer

If you want to append two arrays -  var a     a    b    var b     c    d      then you could use   var c   a concat b     And if you want to add record g to array   var a     then you could use   a push  g

User · Answer

Just want to add a snippet for non-destructive addition of an element    var newArr   oldArr concat  newEl

User · Answer

If you know the highest index  such as stored in a variable  i   then you can do  myArray i   1    someValue    However if you don t know then you can either use   myArray push someValue     as other answers suggested  or you can use  myArray myArray length    someValue     Note that the array is zero based so  length return the highest index plus one   Also note that you don t have to add in order and you can actually skip values  as in  myArray myArray length   1000    someValue    In which case the values in between will have a value of undefined   It is therefore a good practice when looping through a JavaScript to verify that a value actually exists at that point   This can be done by something like the following   if myArray i       undefined    continue      if you are certain that you don t have any zeros in the array then you can just do   if  myArray i    continue      Of course make sure in this case that you don t use as the condition myArray i   as some people over the internet suggest based on the end that as soon as i is greater then the highest index it will return undefined which evaluates to false

User · Answer

If you want to append a single value into an array, simply use the push method. It will add a new element at the end of the array.

But if you intend to add multiple elements then store the elements in a new array and concat the second array with the first array...either way you wish.

arr=['a','b','c'];
arr.push('d');
//now print the array in console.log and it will contain 'a','b','c','d' as elements.
console.log(array);

User · Answer

You can use push method   Array prototype append   function destArray        destArray   destArray             this push call this    destArray        return this    var arr    1 2 5 67   var arr1    7 4 7 8   console log arr append arr1       7  4  7  8  1  4  5  67  7  console log arr append  Hola      1  2  5  67  7  4  7  8   H    o    l    a

User · Answer

We don t have append function for Array in javascript  but we have push and unshift  imagine you have the array below   var arr    1  2  3  4  5     and we like append a value to this array  we can do  arr push 6  and it will add 6 to the end of the array   arr push 6      return  1  2  3  4  5  6     also we can use unshift  look at how we can apply this   arr unshift 0     return  0  1  2  3  4  5     They are main functions to add or append new values to the arrays

User · Answer

The push   method adds new items to the end of an array  and returns the new length  Example   var fruits     Banana    Orange    Apple    Mango    fruits push  Kiwi        The result of fruits will be  Banana  Orange  Apple  Mango  Kiwi   The exact answer to your question is already answered  but let s look at some other ways to add items to an array   The unshift   method adds new items to the beginning of an array  and returns the new length  Example   var fruits     Banana    Orange    Apple    Mango    fruits unshift  Lemon    Pineapple        The result of fruits will be  Lemon  Pineapple  Banana  Orange  Apple  Mango   And lastly  the concat   method is used to join two or more arrays  Example   var fruits     Banana    Orange    var moreFruits     Apple    Mango    Lemon    var allFruits   fruits concat moreFruits       The values of the children array will be  Banana  Orange  Apple  Mango  Lemon

User · Answer

Javascript with ECMAScript 5 standard which is supported by most browsers now  you can use apply   to append array1 to array2   var array1    3  4  5   var array2    1  2    Array prototype push apply array2  array1    console log array2       1  2  3  4  5    Javascript with ECMAScript 6 standard which is supported by Chrome and FF and IE Edge  you can use the spread operator    use strict   let array1    3  4  5   let array2    1  2    array2 push    array1    console log array2       1  2  3  4  5    The spread operator will replace array2 push    array1   with array2 push 3  4  5   when the browser is thinking the logic   Bonus point  If you d like to create another variable to store all the items from both array  you can do this   ES5 var combinedArray   array1 concat array2    ES6 const combinedArray       array1     array2   The spread operator       is to spread out all items from a collection

User · Answer

I think it s worth mentioning that push can be called with multiple arguments  which will be appended to the array in order  For example    x000D   x000D  var arr     first    x000D  arr push  second    third    x000D  console log arr   x000D   x000D   x000D    As a result of this you can use push apply to append an array to another array like so    x000D   x000D  var arr     first    x000D  arr push  second    third    x000D  arr push apply arr    forth    fifth     x000D  console log arr   x000D   x000D   x000D    Annotated ES5 has more info on exactly what push and apply do   2016 update  with spread  you don t need that apply anymore  like    x000D   x000D  var arr     first    x000D  arr push  second    third    x000D   x000D  arr push      fourth    fifth     x000D  console log arr    x000D   x000D   x000D

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Append a single item  To append a single item to an array  use the push   method provided by the Array object   const fruits     banana    pear    apple   fruits push  mango   console log fruits    push   mutates the original array   To create a new array instead  use the concat   Array method   const fruits     banana    pear    apple   const allfruits   fruits concat  mango   console log allfruits    Notice that concat   does not actually add an item to the array  but creates a new array  which you can assign to another variable  or reassign to the original array  declaring it as let  as you cannot reassign a const    const fruits     banana    pear    apple   const allfruits   fruits concat  mango   console log allfruits    let fruits     banana    pear    apple   fruits   fruits concat  mango     Append multiple items  To append a multiple item to an array  you can use push   by calling it with multiple arguments   const fruits     banana    pear    apple   fruits push  mango    melon    avocado   console log fruits    You can also use the concat   method you saw before  passing a list of items separated by a comma   const fruits     banana    pear    apple   const allfruits   fruits concat  mango    melon    avocado   console log allfruits    or an array   const fruits     banana    pear    apple   const allfruits   fruits concat   mango    melon    avocado    console log allfruits    Remember that as described previously this method does not mutate the original array  but it  returns a new array      Originally posted at

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Appending items on an array  let fruits    orange   banana   apple   lemon      array declaration    fruits push  avacado       Adding an element to the array      displaying elements of the array    for var i 0  i  lt  fruits length  i       console log fruits i

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Javascript with ECMAScript 5 standard which is supported by most browsers now  you can use apply   to append array1 to array2   var array1    3  4  5   var array2    1  2    Array prototype push apply array2  array1    console log array2       1  2  3  4  5    Javascript with ECMAScript 6 standard which is supported by Chrome and FF and IE Edge  you can use the spread operator    use strict   let array1    3  4  5   let array2    1  2    array2 push    array1    console log array2       1  2  3  4  5    The spread operator will replace array2 push    array1   with array2 push 3  4  5   when the browser is thinking the logic   Bonus point  If you d like to create another variable to store all the items from both array  you can do this   ES5 var combinedArray   array1 concat array2    ES6 const combinedArray       array1     array2   The spread operator       is to spread out all items from a collection

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We don t have append function for Array in javascript  but we have push and unshift  imagine you have the array below   var arr    1  2  3  4  5     and we like append a value to this array  we can do  arr push 6  and it will add 6 to the end of the array   arr push 6      return  1  2  3  4  5  6     also we can use unshift  look at how we can apply this   arr unshift 0     return  0  1  2  3  4  5     They are main functions to add or append new values to the arrays

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if you want to combine 2 arrays without the duplicate you may try the code below  array merge   function  arr1  arr2      return arr1 concat arr2 filter function item       return arr1 indexOf item   lt  0            usage   array1     1    2    3   array2     2    3    4    5   combined array   array merge array1  array2    Output   1 2 3 4 5

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Append Single Element    Append to the end arrName push  newName1       Prepend to the start arrName unshift  newName1       Insert at index 1 arrName splice 1  0  newName1      1  index number  0  number of element to remove  newName1  new element      Replace index 3  of exists   add new element otherwise  arrName 3     newName1     Append Multiple Elements    Insert from index number 1 arrName splice 1  0  newElemenet1    newElemenet2    newElemenet3      1  index number from where insert starts     0  number of element to remove     newElemenet1 2 3  new elements   Append array    join two or more arrays arrName concat newAry1  newAry2     newAry1 newAry2  Two different arrays which are to be combined  concatenated  to an existing array

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concat    of course  can be used with 2 dimensional arrays as well  No looping required      var a            1  2          3  4          var b             a    b            c    d           b   b concat a         alert b 2  1       result 2

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if you want to combine 2 arrays without the duplicate you may try the code below  array merge   function  arr1  arr2      return arr1 concat arr2 filter function item       return arr1 indexOf item   lt  0            usage   array1     1    2    3   array2     2    3    4    5   combined array   array merge array1  array2    Output   1 2 3 4 5

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Appending items on an array  let fruits    orange   banana   apple   lemon      array declaration    fruits push  avacado       Adding an element to the array      displaying elements of the array    for var i 0  i  lt  fruits length  i       console log fruits i

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If you re only appending a single variable  then push   works just fine  If you need to append another array  use concat      x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  var ar3   ar1 concat ar2   x000D   x000D  alert ar1   x000D  alert ar2   x000D  alert ar3   x000D   x000D   x000D    The concat does not affect ar1 and ar2 unless reassigned  for example    x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  ar1   ar1 concat ar2   x000D  alert ar1   x000D   x000D   x000D    Lots of great info here

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you can do it using new javascript Es 6 feature       initialize array  var arr          Hi        Hello        Bangladesh         append new value to the array  arr      arr    Feni        or you can put a variable value  var testValue    Cool    arr       arr   testValue     console log arr        final output     Hi    Hello    Bangladesh    Feni    Cool

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You can use push and apply function to append two arrays    x000D   x000D  var array1    11  32  75   x000D  var array2    99  67  34   x000D   x000D  Array prototype push apply array1  array2   x000D  console log array1   x000D   x000D   x000D    It will append array2 to array1  Now array1 contains  11  32  75  99  67  34   This code is much simpler than writing for loops to copy each and every items in the array

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With the new ES6 spread operator  joining two arrays using push becomes even easier    x000D   x000D  var arr    1  2  3  4  5   x000D  var arr2    6  7  8  9  10   x000D  arr push    arr2   x000D  console log arr   x000D   x000D   x000D    This adds the contents of arr2 onto the end of arr   Babel REPL Example

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If you are using the ES6 you can use spread operator to do it   var arr          apple        banana        cherry      var arr2          dragonfruit        elderberry        fig      arr push    arr2

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I think it s worth mentioning that push can be called with multiple arguments  which will be appended to the array in order  For example    x000D   x000D  var arr     first    x000D  arr push  second    third    x000D  console log arr   x000D   x000D   x000D    As a result of this you can use push apply to append an array to another array like so    x000D   x000D  var arr     first    x000D  arr push  second    third    x000D  arr push apply arr    forth    fifth     x000D  console log arr   x000D   x000D   x000D    Annotated ES5 has more info on exactly what push and apply do   2016 update  with spread  you don t need that apply anymore  like    x000D   x000D  var arr     first    x000D  arr push  second    third    x000D   x000D  arr push      fourth    fifth     x000D  console log arr    x000D   x000D   x000D

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concat    of course  can be used with 2 dimensional arrays as well  No looping required      var a            1  2          3  4          var b             a    b            c    d           b   b concat a         alert b 2  1       result 2

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You can use the push   if you want to add values e g  arr push  Test1    Test2     If you have array you can use concat   e g  Array1 concat Array2   If you have just one element to add you can also try length menthod e g  array aray length     test

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If you re only appending a single variable  then push   works just fine  If you need to append another array  use concat      x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  var ar3   ar1 concat ar2   x000D   x000D  alert ar1   x000D  alert ar2   x000D  alert ar3   x000D   x000D   x000D    The concat does not affect ar1 and ar2 unless reassigned  for example    x000D   x000D  var ar1    1  2  3   x000D  var ar2    4  5  6   x000D   x000D  ar1   ar1 concat ar2   x000D  alert ar1   x000D   x000D   x000D    Lots of great info here

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If you are using the ES6 you can use spread operator to do it   var arr          apple        banana        cherry      var arr2          dragonfruit        elderberry        fig      arr push    arr2

[javascript] How to append something to an array?

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