name is special

[richlim]

TypeScript Version:

Version 1.9.0-dev.20160417

Code

// A self-contained demonstration of the problem follows...
let name: string = "hallo";

Expected behavior:
compile

Actual behavior:
error TS2451: Cannot redeclare block-scoped variable 'name'.

[DanielRosenwasser]

The issue is that there's always a name when you're running in a browser environment:

https://developer.mozilla.org/en-US/docs/Web/API/Window/name

In TypeScript 2.0, you'll be able to exclude the definition using the lib flag if you're running in, say, Node.js.

[DanielRosenwasser]

See also #8107.

[richlim]

Then maybe the TypeScript documentation should be changed?
In Basic Types:String:
let name: string = "bob";

[DanielRosenwasser]

I already have fixed this at microsoft/TypeScript-Handbook#251, so we'll just need to republish the docs to the website.

[ocombe]

@DanielRosenwasser is there anyway to get more context on where this "name" variable is defined ? I'm only getting ERROR in [default] C:\www\front-portal-v2\node_modules\typescript\lib\lib.d.ts:18448:14 Cannot redeclare block-scoped variable 'name'. but there are no details as to where it is in my code, and I cannot find it :(

[mhegazy]

you should see another error for the other file, something like:

./node_modules/typescript/lib/lib.d.ts(18454,15): error TS2451: Cannot redeclare block-scoped variable 'name'.
./test/a.ts(1,5): error TS2451: Cannot redeclare block-scoped variable 'name'.

[ocombe]

no I'm not, that's the problem :(

[mhegazy]

how are your running your compiler? what version of tsc are you using? can you share a repro?

[ocombe]

I'm using webpack 1.x with awesome-typescript-loader and typescript 2.0.2
I cannot share a repro as it is happening in a private work project and if I knew what was causing the problem in my code I'd fix it :D
I've downgraded to ts 2.0 for now

[mhegazy]

so if you run tsc on the tsconfig directly not through awesome-typescript-loader, do you see the error?

[ocombe]

I retried with just tsc, no error, it builds the project just fine, I guess the problem lies within awesome-typescript-loader then :)

[mhegazy]

I retried with just tsc, no error, it builds the project just fine,

what version of tsc were you using? this change was introduced in TS 2.0.

[ocombe]

I was using 2.0.0 before, and updated to 2.0.2, I updated awesome-typescript-loader from 2.2.1 to 2.2.4 at the same time

[mhegazy]

that is not what i would expect. i would expect an error message for re-declaring a block-scoped variable. i would be interested to see a repro project if one is available.

[ocombe]

Ok, as it turns out the problem was with zone.js that was polluting the global namespace and replacing window.name (angular/zone.js#456), I just updated zone.js and the error disappeared !