Rule proposal: Forbid imports with explicit side-effects #529

IMO, modules that have side-effect just from requiring them are really bad. I would like to see a rule that forbids importing/requiring modules that are not assigned, which implicitly means there is a side-effect or simply not used and therefore useless.

Invalid

import 'dosideeffect';
import './dosideeffect';
require('./dosideeffect');

Valid

import foo from 'bar';

// Explicit effect
import doEffect from './dosideeffect';
doEffect();

As far as rule name goes: no-unnassigned-import, no-side-effect-import, ...? I'm leaning toward the former at the moment, though it doesn't capture the rationale of it.