code: function isEntirely(str, char) {
    let charCode = char.charCodeAt();
    for (let i = 0; i < str.length; i++) {
      let strCode = str[i].charCodeAt();
      if (strCode != charCode && (consts.caseSensitive || strCode != changeCase(charCode))) return false;
    }
    return true;
  }
docs: /* Check if a string is entirely composed of the given character. True if empty string.
  * Seems to execute faster than constructing a regexp.
  *