Explanation requested for fixedEncodeURIComponent

Question

I'm wondering if anyone can explain this function to me? I've tested it and it works like a dream but I don't understand how!

It's from the MDN reference here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent

function fixedEncodeURIComponent (str) {
  return encodeURIComponent(str).replace(/[!'()]/g, escape).replace(/\*/g, "%2A");
}

I understand replace as the match followed by the replacement, what I am struggling with is the escape reference and the secondary replacement which results in actual encode values replacing characters e.g. ( = %28 and )= %29.

Answer 1

The reference to "escape" is just a reference to the global function of that name. If the second argument to .replace() is a function, then JavaScript passes the matched string to the function and replaces it with whatever the function returns.

Try typing

escape("!")

in your browser's console.