for...of iterator fail with `FormData.entries()`

[KhaledElAnsari]

Hello,

I was trying to iterate through the FormData values with the .entries() function using for...of iterator and it failed! I tried to do the same thing with other transpiler and it worked!

TypeScript Version: 2.0.10
Browser Used: Chrome 55.0.2883.87, FireFox 50.1.0
Code

// same simple MDN example
let formData = new FormData();
formData.append('key1', 'value1');
formData.append('key2', 'value2');
for(let pair of formData.entries()) {
   console.log(pair[0] + ": ", pair[1]); 
}

Expected behavior:

Nothing was printed in the console

Actual behavior:

key1: value1
key2: value2

[hzoo]

I didn't mean that this needed to be a new issue, in #3164 (comment)

I think @mhegazy already explained why TypeScript isn't supporting it unless you are compiling to ES6, otherwise you can use TS -> Babel

[KhaledElAnsari]

@hzoo did't see that :\ but it explains a lot! thanks

[aluanhaddad]

This is no longer the case. #12346

[hzoo]

Oh right 👍 forgot about that.

[arciisine]

I'm experiencing the same behavior, running in node 7. My work around was to wrap the .entries() call with Array.from(...). I'm inclined to believe it's a Node issue.

[aluanhaddad]

@arciisine This feature has not yet landed for --target < es2015
Since you are on Node 7. You can use --target >= es2015 and it will just work.

[arciisine]

I am using the target es2015 and I had the same issue that the loop was not iterating. I had to add Array.from to get the loop to iterate properly.

Edit: Running basic tests, Map.entries() is fine with target es2015. I definitely hit this issue before (with target es2015) but I have also hit some other odd edge cases, so it may be something to do with my setup.

[blakeembrey]

@arciisine What's the error you're getting? There's no FormData object natively in node.

[arciisine]

The error was wrt to iterating on map.entries(), and the iteration being skipped unless I wrapped map.entries() in Array.from(...). I'm assuming it is something to do with the Iterator construct vs having an array. That is to mean, nothing specific with FormData but Map.

[ollwenjones]

Just ran across this issue with Map.entries() (and .values() and .keys()) Why doesn't TS follow the spec? Or is MDN wrong about the for...of loop working on Map?
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map

[mhegazy]

Should be fixed by #14859 in TS 2.3.

if you are using --lib option in your tsconfig.json make sure you add dom.iterable