SyntaxError: 'return' outside of function

[scriby]

The acorn parser is throwing an error on a node source file with a return statement at the top level. I'm not certain whether this is technically valid or not, but it works in V8 and I know the uglify parser allows it.

[michaelficarra]

JavaScript does not allow return outside function bodies. Acorn and Esprima both handle this correctly. You should open an issue with UglifyJS about this. See nodejs/node-v0.x-archive#6254 for why it is allowed in node. tl;dr: It's a side effect of a hack they used to introduce special node "global"s, and they've opted for performance over correctness.

[mishoo]

@michaelficarra He is mistaken, UglifyJS does not allow it either.

[marijnh]

Still, for Tern, which needs to parse node code (without the wrapping function kludge being visible), I guess I should add an option to allow this. Implemented in attached patch. I'll push something to Tern to enable it there.

[scriby]

Thanks for the patch. I was incorrect about Uglify, looks like I had changed that in my fork. I tested Esprima and it doesn't allow it. The TypeScript compiler does allow it.

(I'm not just being pedantic, I do actually have a good use case for returning from the top level of the script :))

[michaelficarra]

@scriby: I don't think you do. You can always use a top-level IIFE and return from within there.

[scriby]

I consider it worthwhile to not have to wrap the entire module in a function, which increases indentation level unnecessarily.

[NeamahAlskeini]

Hi all
When I run aling_dataset_mtcnn.py, I get this error!!
File "align_dataset_mtcnn.py", line 162
return parse.parse_args(argv)
SyntaxError: 'return' outside function

Any one could help to fix this issue?

Regards
Neamah

[fabiosantoscode]

To future googlers, add the allowReturnOutsideFunction option.