push multiple elements to array

Question

I m trying to push multiple elements as one array  but getting error   gt  a          gt  a push apply null   1 2   TypeError  Array prototype push called on null or undefined   I m trying to do similar stuff that I d do in ruby  I was thinking that apply is something like      gt  gt  a        gt      gt  gt  a push   1 2     gt   1  2

User · Accepted Answer

When using most functions of objects with apply or call, the context parameter MUST be the object you are working on.

In this case, you need a.push.apply(a, [1,2]) (or more correctly Array.prototype.push.apply(a, [1,2]))

User · Answer

If you want an alternative to Array concat in ECMAScript 2015  a k a  ES6  ES2015  that  like it  does not modify the array but returns a new array you can use the spread operator like so    x000D   x000D  var arr    1   x000D  var newItems    2  3   x000D  var newerItems    4  5   x000D  var newArr       arr     newItems     newerItems   x000D  console log newArr   x000D   x000D   x000D    Note this is different than the push method as the push method mutates modifies the array   If you want to see if certain ES2015 features work in your browser check Kangax s compatibility table   You can also use Babel or a similar transpiler if you do not want to wait for browser support and want to use ES2015 in production

User · Answer

Pushing multiple objects at once often depends on how are you declaring your array  This is how I did   declaration productList     as  any   now push records this productList push obj lenght  obj2 lenght  items

User · Answer

If you want to add multiple items  you have to use the spread operator a    1 2  b    3 4 5 6  a push    b   The output will be a    1 2 3 4 5 6

User · Answer

There are many answers recommend to use  Array prototype push a  b   It s nice way  BUT if you will have really big b  you will have stack overflow error  because of too many args   Be careful here   See What is the most efficient way to concatenate N arrays  for more details

User · Answer

Now in ECMAScript2015  a k a  ES6   you can use the spread operator to append multiple items at once    x000D   x000D  var arr    1   x000D  var newItems    2  3   x000D  arr push    newItems   x000D  console log arr   x000D   x000D   x000D    See Kangax s ES6 compatibility table to see what browsers are compatible

User · Answer

var a     a push    name a  abc    b         a b push     name b  xyz

User · Answer

You can use Array concat   var result   a concat b

User · Answer

You can push multiple elements into an array in the following way   x000D   x000D  var a       x000D       x000D  a push 1  2  3   x000D   x000D  console log a   x000D   x000D   x000D

[javascript] push multiple elements to array

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