Emit __esModule for every ES6 module emitted.

[mhegazy]

In anticipation for change by the Node CTC to adopt ES6 modules, transpiled modules should all have the flag set. this gives an unambiguous way to know if this is a trsanspiled module of a plain old CJS module.

[yuit]

Export __esModule for all module except when there is export =
Update: such export should be before calling of require to facilitate circular dependency

[pjordaan]

so how can I configure to disable this emit? I get errors that exports is not defined. And I also see a few related tickets to other projects where this happens too.

[yume-chan]

@pjordaan I believe it's a bug, as a workaround you can set module: typescript.ModuleKind.ES2015 in compiler options to get rid of __esModule, I don't know why but ES2015 modules are not affected.

Dev Team think it works as intended, see the referecned bug for discussion.

[ghost]

Can the emit be either:

Object.defineProperty(exports || {}, "__esModule", { value: true });

or

if( typeof exports !== 'undefined' ) Object.defineProperty(exports, "__esModule", { value: true });

?

[RyanCavanaugh]

@errorx666 why?

[ghost]

@RyanCavanaugh I'm using SystemJS with commonjs modules. For a file that has neither imports nor exports, System.import( 'foo' ); does not recognize the file as a module, and so does not define exports (or module, etc). So, the browser throws an error that exports is undefined when we try to define a property on it.

Currently working around this with

export = void 0;

at the bottom of each file.

[pjordaan]

Same here, but I'm using rollup as a bundler. Not all setups result in a variable exports and this just breaks development for me. If I understand correctly this is only there as hack for running Typescript in node.js.

And shouldn't it be
if (typeof exports !== 'undefined') in case you are in strict mode.

[farfromrefug]

any news on this? I also get the error that exports is not defined in my react app (electron).
I am stuck with 2.1.4 until this is resolved.

[brian428]

There seems to be a lot of debate on this in various issue threads, but the bottom line is that this change is totally wrecking the ability for a lot of people to upgrade to 2.2.x. If a file has no exports, why is this still being emitted? And if the TS team won't suppress this for files without exports, then at least make the ridiculously simply change to have it emit Object.defineProperty(exports || {}, "__esModule", { value: true }); so that it doesn't completely break people's code.

[scf37]

I'm using typescript together with Google Closure Compiler and __esModule has no value there.