Creating a filled array with a given length?

Rick Waldron waldron.rick at gmail.com
Wed Dec 12 08:08:18 PST 2012


On Wed, Dec 12, 2012 at 1:59 AM, Axel Rauschmayer <axel at rauschma.de> wrote:

> I would still love to have something like that in ES6 (loosely similar to
> String.prototype.repeat). Once you have that, you can e.g. use
> Array.prototype.map to do more things.
>
> Two possibilities:
> - Array.repeat(undefined, 3) -> [ undefined, undefined, undefined ]
> - [ undefined ].repeat(3) -> [ undefined, undefined, undefined ]
>
> The same array could be created like this, but that seems too much work
> for a relatively common operation.
>
> 'x'.repeat(3).split('').map(=> undefined)
>

Array Comprehensions!

This is probably wrong, so treat it more like an idea and less like a
matter of fact:

[ undefined for x of new Array(3) ].map( v => ... );

[ undefined for x of [0,0,0] ].map( v => ... );


Rick
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