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Groups > comp.lang.javascript > #30285

Re: duplicator an array

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On 16/04/2016 12:01, Joao Rodrigues wrote:
> On 16/04/2016 09:27, Stefan Weiss wrote:
>
>>
>> By the way, ES2015 introduced the spread operator `...`.
>> With this operator, you can also write
>>
>>     this.push(...this.slice(0))
>>
>> instead of
>>
>>     this.push.apply(this, this.slice(0))
>>
>
> Yeah, the spread operator makes life a lot easier: [1]:
>
>     let arr1 = ['a', 'b'];
>     let arr2 = ['c'];
>     let arr3 = ['d', 'e'];
>
>     console.log([...arr1, ...arr2, ...arr3]);
>     // [ 'a', 'b', 'c', 'd', 'e' ]
>
> [1] <http://www.2ality.com/2015/08/getting-started-es6.html>
>

As an exercise, the OP's code might be rewritten in ES6 to:

Array.prototype.duplicator = function () {
   return [...this, ...this];
};
[1,2,3,4,5].duplicator();
// [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]

Tested with latest versions of MS Edge, Chrome and FF.

--
Joao Rodrigues

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duplicator an array JRough <janis.rough@gmail.com> - 2016-04-13 18:27 -0700
  Re: duplicator an array Aleksandro <aleksandro@gmx.com> - 2016-04-14 01:00 -0300
    Re: duplicator an array JRough <janis.rough@gmail.com> - 2016-04-14 09:53 -0700
    Re: duplicator an array "Christoph M. Becker" <cmbecker69@arcor.de> - 2016-04-14 19:41 +0200
      Re: duplicator an array Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-04-14 22:09 +0200
        Re: duplicator an array Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-04-14 22:23 +0200
    Re: duplicator an array Stefan Weiss <krewecherl@gmail.com> - 2016-04-16 14:27 +0200
      Re: duplicator an array Joao Rodrigues <jr@none.com> - 2016-04-16 12:01 -0300
        Re: duplicator an array Joao Rodrigues <jr@none.com> - 2016-04-16 13:43 -0300
      Re: duplicator an array Aleksandro <aleksandro@gmx.com> - 2016-04-16 14:13 -0300
  Re: duplicator an array bharat.bandgar009@gmail.com - 2017-05-03 01:33 -0700

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