JavaScript language plugin query selector sometimes doesn't find selectors

[ericcornelissen]

Bug Report

packages/core v0.1.23

Description

The built-in JavaScript language plugin is sometimes unable to find query selectors. The issue seems to be due to the fact that it gets stuck in what is not actually a string between two strings, and then ignoring the following string. The following snippet of JavaScript can be used to reproduce the bug using the pattern [a-z]+:

'';
var foo = 'bar';
'';

which should return "bar" but in fact doesn't return anything.