Standard lib function to convert generators to an array? about traceur-compiler HOT 5 CLOSED

From [email protected] on June 23, 2012 20:24:02
var arr = [x for x of generator]

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From [email protected] on June 25, 2012 03:12:36
Oh, is harmony getting array comprehensions? That's awesome! If so, I agree that a separate function isn't really needed. I was afraid I'd have to write something ugly like:

var arr = [];
for (var x of generator) {
arr.push(x);
}

I guess the larger question here is: will generators get the nice Array.prototype functions like map, reduce, filter, any, some etc (https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/prototype)? It'd be nice to be able to do things like "generator.map((x) => x + 1)" ... if all of the nice functions work then conversion becomes less important.

Although even then, I guess you can get pretty far with just comprehensions!

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From [email protected] on June 25, 2012 04:23:29
Generator and Array comprehensions are in the latest ES6 draft (generator one is not complete). I added support for it in Traceur last week.

Firefox makes all generators/iterators share the same prototype. It is not available by name but you can get to it by getting the constructor of a iterator.

function g() { yield 42 }
g().constructor.prototype.map = function(f) {
for (let item of this) {
yield f(item);
}
};

function h() { yield 1; yield 2 }
i = h().map(function(item) { return item * item })
[x for (x of i)] // SpiderMonkey syntax is not compatible with ES6

Traceur does not share the prototype. We should probably fix that.

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Closing this since ES6 had [...iterable] even though that might be deferred to ES7 :'(

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Correction... [...iterable] is in ES6... I got confused there for a while (I was thinking of array comprehensions).

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