How to add a new object key-value pair to an array in javascript

Question

I have an array as      items    id  1    id  2    id  3    id  4      How should I add a new pair   id  5  to the array

User · Answer

push   will add elements to the end of an array   Use  unshift   if need to add some element to the beginning of array i e   items unshift   id  5      Demo    x000D   x000D  items      id   1     id   2     id   3     id   4    x000D  items unshift   id   0    x000D  console log items   x000D   x000D   x000D    And use  splice   in case you want to add object at a particular index i e   items splice 2  0    id  5                    Given object will be placed at index 2      Demo    x000D   x000D  items      id   1     id   2     id   3     id   4    x000D  items splice 2  0    id   2 5    x000D  console log items   x000D   x000D   x000D

User · Answer

If you re doing jQuery  and you ve got a serializeArray thing going on concerning your form data  such as     var postData       yourform   serializeArray        postData  array with objects          name   firstname   value   John     name   lastname   value   Doe    etc       and you need to add a key value to this array with the same structure  for instance when posting to a PHP ajax request then this     postData push   name    phone    value    1234-123456       Result      postData         name   firstname   value   John     name   lastname   value   Doe      name   phone   value   1234-123456

User · Answer

Use  push   items push   id  5

User · Answer

Sometimes  concat   is better than  push   since  concat   returns the new array whereas  push   returns the length of the array    Therefore  if you are setting a variable equal to the result  use  concat     items      id   1     id   2     id   3     id   4    newArray   items push   id  5     In this case  newArray will return 5  the length of the array    newArray   items concat   id   5     However  here newArray will return    id   1     id   2     id   3     id   4     id   5

User · Answer

New solution with ES6  Default object  object      id   1     id   2     id   3     id   4      Another object  object      id   5     Object assign ES6  resultObject       obj     newobj     Result     id   1     id   2     id   3     id   4     id   5

[javascript] How to add a new object (key-value pair) to an array in javascript?

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