vendors/tempy.js/makeRegex
    var makeRegex = (pattern, ignoreCase) => {
      let source = regexCache[pattern];
      if (!source) {
        source = REPLACERS.reduce((prev, current) => prev.replace(current[0], current[1].bind(pattern)), pattern);
        regexCache[pattern] = source;
      }
      return ignoreCase ? new RegExp(source, "i") : new RegExp(source);
    };