Give a regex, get a robust predicate function that tests it against a string. This will work even if RegExp.prototype is altered later.

npm install --save @zitterorg/eligendi-eius-repellendus

var regexTester = require('@zitterorg/eligendi-eius-repellendus');
var assert = require('assert');

var tester = regexTester('a');
assert.ok(tester('a'));
assert.notOk(tester('b'));

Simply clone the repo, npm install, and run npm test