Side-effect of (0, obj.method)() is warned as no side-effect

[jameshartig]

Babel produces code that utilizes (0, obj.method)() in order to make a function call without the context being obj since obj is just a placeholder object for the methods that were imported.

When running code through Closure Compiler, it produces a warning:

JSC_USELESS_CODE: Suspicious code. This code lacks side-effects. Is there a bug? at line 165
dateStart = (0, _utilities.dateNow)();

That code does have the side-effect of calling dateNow without the context of _utilities.

The original code (before babel) stems from:

import { dateNow } from './utilities';
...
dateStart = dateNow();

[MatrixFrog]

I assume it means that the '0' lacks side-effects.

In general, it's likely that Babel outputs lots of code that is valid but will produce warnings in Closure Compiler.

[ChadKillingsworth]

I would think this is super low priority. But we'd entertain a pull request to have the compiler recognize this pattern.