function createPad(string, length, chars) {
      var strLength = string.length;
      length = +length;

      if (strLength >= length || !nativeIsFinite(length)) {
        return '';
      }
      var padLength = length - strLength;
      chars = chars == null ? ' ' : String(chars);
      return repeat(chars, ceil(padLength / chars.length)).slice(0, padLength);
    }
Creates the pad required for `string` based on the given padding length.
The `chars` string may be truncated if the number of padding characters
exceeds the padding length.

@private
@param {string} string The string to create padding for.
@param {number} [length=0] The padding length.
@param {string} [chars=' '] The string used as padding.
@returns {string} Returns the pad for `string`.