Exporting a keyword-named function in a module

[panuhorsmalahti]

The type definition file for the Q module has the following problem:

 //export function try(method: Function, ...args: any[]): Promise<any>; // <- This is broken currently - not sure how to fix.

The compiler doesn't accept the type definition because it thinks a try/catch block is about to begin.

q/Q.d.ts(204,21): error TS1006: Identifier expected; 'try' is a keyword.
q/Q.d.ts(204,24): error TS1005: '{' expected.
q/Q.d.ts(204,72): error TS1005: '=>' expected.

Is there any way to define this exported function?

[mikaturunen]

👍
I need this information also.

[danquirk]

This isn't allowed at the moment because JavaScript doesn't allow that pattern either. Presumably Q has actually defined it as something like module.exports.try = function() {}. We could start allowing you to use keywords for export var names to support this.

In the meantime one workaround would be to use a merged class and module.

declare class Q {
    static try();
}

declare module Q { }

Q.try();

The downside here is that now the type system will think Q has a construct signature and a prototype property.

[adamvoss]

I also encountered this or a variation thereof.

I was trying to do a literal port of the following JavaScript,

exports.delete = function(args) { ... }

but, could not use the following TypeScript

export function delete(args) { ... }

In the end I found the JavaScript version still works in the TypeScript file and had to stick with that for this function.

[DanielRosenwasser]

Related is #9846. If I recall, we decided that it was too complex because you can rewrite your module as follows:

// Exported values go here.
interface X {
    delete(args: any[]): void;
}

// Exported types go here.
declare namespace x {
    interface Foo {
         // ...
    }
}

declare var x: X;
export = x;

[aluanhaddad]

@vossad01, @DanielRosenwasser I'm curious why not use this instead.

function del(...args) { }

export { del as delete }

turns out this errors on import, sigh...