Simplify the use of indexOf

better-index-of.js

// Array
var list = ['my', 'str', 'list'];

if (~list.indexOf('my')) {
  console.log('the `list` array contains \'my\'');
}

if (!~list.indexOf('number')) {
  console.log('the `list` array does not contain \'number\'');
}

// String
var hello = 'world';

if (~hello.indexOf('orl')) {
  console.log('`hello` contains \'orl\'');
}

if (!~hello.indexOf('qsd')) {
  console.log('`hello` does not contain \'qsd\'');
}

See https://github.com/loverajoel/jstips#15---even-simpler-way-of-using-indexof-as-a-contains-clause