Flow: "Illegal return statement" at top level of Node.js module

[talbenari1]

The following code is a completely valid module in Node.js:

return;

This is because of the function that wraps all Node modules:

(function (exports, require, module, __filename, __dirname) {
    // code gets "injected" here
});

However, Flow hits a parse error and throws "Illegal return statement" for the file. Is there a way to avoid the parse error without wrapping the entire module in a pointless IIFE?

Somewhat related: #6351

[jbrown215]

What's your use case for this? Exposing that implementation detail at the type level seems like it adds complexity for little benefit.

[talbenari1]

Well, one example would be short-circuiting behavior in a script (e.g. processing command-line arguments) without prematurely exiting the process (a la process.exit()) so that other async events can finish.

[jcready]

How about this:

/*:: (function (exports, require, module, __filename, __dirname) { */
return;
/*:: })(); */

[talbenari1]

Actually yeah, that would solve it. Don't know why I hadn't thought of doing that, thanks @jcready :smile: