Symbol.interator for array of numbers?

[sant123]

TypeScript Version: Playground.

Hi, in the playground version I found this:

Code

function myFunc() {
    let items = [1, 2, 3, 4, 5];

    for (let item of items) {
        console.log(item);
    }
}

Expected behavior:
No error.

Actual behavior:
An error.

In normal JS this is not an error:

[kitsonk]

That seems to be a really odd configuration of Playground that is causing it with the release of TypeScript 2.0. It seems like the Playground is sort of stuck between ES5 and ES6. The emit is ES5, but the syntax checking is ES6 but without the proper libraries loaded.

Running locally, both targeting ES5 and ES6 that works without issue.

[sccolbert]

Another example:

[sant123]

That's right @kitsonk, but only occurs in the playground. Also async and generator statements are "compiled" with no problems, but the result code is not compatible with ES5 and below. I've tested it with VS Code too but I do not get problems.

[sccolbert]

I get this error when running the code above targeting ES5 output. i.e. not limited to playground for me:
error TS2346: Supplied parameters do not match any signature of call target.

[kitsonk]

@sccolbert did that ever work? I think what you are proposing is covered by #5296 which is still just a proposal.

[sccolbert]

@kitsonk I could have sworn it used to be translated to a foo.apply(void 0, values) call...

[sccolbert]

For example, this compiles fine on TS 1.8:

var values: number[] = [1, 2, 3, 4, 5];
var data: number[] = [];

data.push(...values);

But as you mentioned, the original code I posted does not. Which is doubly strange :)

[jasongrout]

For example, this compiles fine on TS 1.8:

And that code seems fine on playground too: http://www.typescriptlang.org/play/#src=var%20values%3A%20number%5B%5D%20%3D%20%5B1%2C%202%2C%203%2C%204%2C%205%5D%3B%0D%0Avar%20data%3A%20number%5B%5D%20%3D%20%5B%5D%3B%0D%0A%0D%0Adata.push(...values)%3B

[mhegazy]

this is an issue with the playground. we recently updated to the latest version of monco-editor and that seems to set the target to ES6 all the time. i will see if i can get a fix for this soon. sorry for the confusion.

Iterators are only supported when your targeting ES6. so for .. of only works in ES6. and you should get an error indicating this otherwise.

[sccolbert]

Sounds like my example is a red herring (sorry).

[mhegazy]

Should be fixed now. sorry about the confusion.