Whenever I work with arrays, I always use the [] style, however, when I want to create an array with a fixed amount of elements I use new Array(N) (I don't know any other way of doing this)

I thought it wasn't big deal, until I read these strong words about this:

Anyone doing this, using “new Array()” instead of “[]“, or “new Object()” instead of “{}” needs to relearn JavaScript.

I really want to avoid writting bad code. Anyone mind tell me the right direction to go?

Whenever I work with arrays, I always use the [] style, however, when I want to create an array with a fixed amount of elements I use new Array(N) (I don't know any other way of doing this)

I thought it wasn't big deal, until I read these strong words about this:

Anyone doing this, using “new Array()” instead of “[]“, or “new Object()” instead of “{}” needs to relearn JavaScript.

I really want to avoid writting bad code. Anyone mind tell me the right direction to go?

• javascript
• arrays

• 2 I actually think you're fine already. You're using the [] syntax when you allocate an array most of the time, and new Array(n) when you want a specific size. Nothing wrong there, the quote you posted doesn't account for all situations. – Michael Berkowski Commented Feb 12, 2012 at 3:13
• @Michael good to know!, I guess I can now sleep with the lights off :) – mithril333221 Commented Feb 12, 2012 at 3:16
• 1 I see nothing wrong with using the Array constructor in this manner. It exists for a good reason. – Jeremy Roman Commented Feb 12, 2012 at 3:18
• @mithril333221 I'll check back in case someone enlightens me, but I don't know of another way to pre-allocate array size either short of [null,null,null,null,...] – Michael Berkowski Commented Feb 12, 2012 at 3:19
• 1 @LightnessRacesinOrbit on the ments of andrewdupont/2006/05/18/… – mithril333221 Commented Feb 12, 2012 at 3:32

4 Answers 4

I wouldn't worry too much about some random ment on a blog in 2006. Especially since your use case isn't just new Array(). You're using the special-case constructor that is provided specifically for this purpose.

Besides, using new Array() instead of [] is hardly the worst thing someone can do with JS.

function repeat(str, len){
    str= str || '';
    len= len || 1;
    return Array(len+1).join(str);
}

repeat('*',25)

// returned value: (String)

I know this question is pretty old, but here's how I would code it as an alternative to new Array(size), using JavaScript's literal syntax.

var arr = [];
arr.length = size;

You can use Array.from to create an array with n elements.

Ex. Create array of zeros with length 7.

let arr = Array.from({length: 7}, () => 0);

!! Array.from is not supported by IE so use with caution.