Check if text is in a string

if(str.indexOf(str2) >= 0) {
   ...
}

Or if you want to go the regex route:

if(new RegExp(str2).test(str)) {
  ...
}

However you may face issues with escaping (metacharacters) in the latter, so the first route is easier.

ES5

if(str.indexOf(str2) >= 0) {
   ...
}

ES6

if (str.includes(str2)) {

}