RE: How to correctly spec sequences requiring an iterable

From: Boris Zbarsky <bzbarsky@MIT.EDU>

> But maybe I misunderstand the performance cost you're worrying about?

Well, I'm not sure, so let me restate it just in case.

Let's say I pass a sequence containing 1000 numbers to such a function. Your proposed behavior is, from what I understand,

```js
function frobEachElement(sequence) {
  var array = [];
  for (var el of sequence) {
    array.push(Number(el));
  }

  array.forEach(frob);
}
```

So you do a total of 2000 iterations. Whereas the "idiomatic" way would be

```js
function frobEachElement(sequence) {
  for (var el of sequence) {
    frob(Number(el));
  }
}
```

which only does 1000 iterations.

Thoughts?

Received on Monday, 18 November 2013 18:20:01 UTC