What is the easiest way to insert a new object into an array of objects at the index position 0? No jQuery; MooTools okay; no unshift() because it's undefined in IE according to w3schools.
views:
239answers:
4
+6
A:
Using splice method.
array.splice(index,howmany,element1,.....,elementX);
For inserting, 'howmany' = 0
o.k.w
2010-02-04 05:10:57
`unshift` and `concat` are simpler than `splice` for what @JamesBrownIsDead wants to do.
Dominic Cooney
2010-02-04 05:22:33
@Dominic, very true indeed. I guess I'm just 'lazy' to remember different methods and just the more generic ones :P
o.k.w
2010-02-04 05:41:35
@o.k.w splice is nice :)
Dominic Cooney
2010-02-04 23:59:17
+18
A:
W3CSchools is really outdated, the unshift method is part of the ECMAScript 3rd Edition standard which was approved and published as of December 1999.
There is no reason to avoid it nowadays, it is supported from IE 5.5 up.
It is safe to use it, even modern libraries like jQuery or MooTools internally use it (you can check the source code :).
var array = [2,3];
array.unshift(1); // returns 3
// modifies array to [1, 2, 3]
This method returns the new array length, and inserts the element passed as argument at the first position of the array.
CMS
2010-02-04 05:11:01
The questioner specifies no `unshift` because w3schools says it is unsupported in IE. As @CMS points out, that is out-of-date: w3schools doesn't even *track* IE<6 market share any more.
Dominic Cooney
2010-02-04 05:19:50
Alconja
2010-02-04 05:43:45
@CMS: almost edited your response myself to let me change my vote, but I figured that was a bit rude. :) Anyway, I've switched it to an up-vote now. Well deserved.
Alconja
2010-02-04 09:49:48
+5
A:
You can try this:
var newItem = 3;
arr = [newItem].concat(arr);
Another option is to use push and reverse the indices - you can easily write an object that does that.
Kobi
2010-02-04 05:11:36
A:
I would use unshift() if your intent is to modify the array, otherwise you can use concat() as Kobi suggested (which returns a new array and does not modify the involved arrays):
var arr = [1, 2], newItem = 3;
var newArr = [newItem].concat(arr); // newArr = [1, 2, 3], arr still = [1, 2]
See: concat
kflorence
2010-06-24 18:13:55