SyntaxError showing token not in the input

[msridhar]

• Version: v6.0.0
• Platform: Mac OS X 10.11.4

Givenfoo.js just containing the following:

++

When I run node foo.js, I get:

/private/tmp/foo.js:3
});
^
SyntaxError: Unexpected token }
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:511:25)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:456:32)
    at tryModuleLoad (module.js:415:12)
    at Function.Module._load (module.js:407:3)
    at Function.Module.runMain (module.js:575:10)
    at startup (node.js:159:18)
    at node.js:444:3

But the token } does not appear in foo.js. This could be related to #3411, not sure. When I run with just v8, I get an appropriate error:

/tmp/foo.js:1: SyntaxError: Unexpected end of input
++
^^
SyntaxError: Unexpected end of input

[cjihrig]

I think this is expected due to Node wrapping your code.

[mscdex]

Yes, the reason it does not point to your ++ line is because the parser is expecting a variable afterwards somewhere (even on a following line). So it instead sees } from the node module wrapper function which is not a valid variable name token and exits. You can verify this is the case with:

var n = 0;
++

n

console.log(n) // Prints `1`

[msridhar]

To be clear, this is not a serious bug for me; I just wanted to report it in case it was indicative of some more important problem. Is this whole "node module wrapper function" behavior documented somewhere? It seems unfortunate that it can lead to such a confusing SyntaxError. But, it might not be worth it to fix this one.

[cjihrig]

I'm not sure if it's actually documented. Interestingly enough, the docs do say:

Variables local to the module will be private, as though the module was wrapped in a function. In this example the variable PI is private to circle.js.

Where "as though" could be interpreted as "because" :-)

[mtharrison]

Doesn't seem to be documented anywhere. Might be useful to include so I made a PR: #6433

[stevemao]

I think this is expected due to Node wrapping your code.

I feel user shouldn't know about this. At least the error shouldn't point to the internally code });.

[cjihrig]

This was closed a while back in 7164003.