Symbol.replace

The Symbol.replace static data property represents the well-known symbol Symbol.replace. The String.prototype.replace() and String.prototype.replaceAll() methods look up this symbol on their first argument for the method that replaces substrings matched by the current object.

For more information, see RegExp.prototype[Symbol.replace](), String.prototype.replace(), and String.prototype.replaceAll().

class CustomReplacer {
  constructor(value) {
    this.value = value;
  }
  [Symbol.replace](string) {
    return string.replace(this.value, "#!@?");
  }
}

console.log("football".replace(new CustomReplacer("foo"))); // "#!@?tball"