function pad(string, length, chars) {
	      string = baseToString(string);
	      length = +length;

	      var strLength = string.length;
	      if (strLength >= length || !nativeIsFinite(length)) {
	        return string;
	      }
	      var mid = (length - strLength) / 2,
	          leftLength = nativeFloor(mid),
	          rightLength = nativeCeil(mid);

	      chars = createPadding('', rightLength, chars);
	      return chars.slice(0, leftLength) + string + chars;
	    }
Pads `string` on the left and right sides if it's shorter than `length`.
Padding characters are truncated if they can't be evenly divided by `length`.

@static
@memberOf _
@category String
@param {string} [string=''] The string to pad.
@param {number} [length=0] The padding length.
@param {string} [chars=' '] The string used as padding.
@returns {string} Returns the padded string.
@example

_.pad('abc', 8);
// => '  abc   '

_.pad('abc', 8, '_-');
// => '_-abc_-_'

_.pad('abc', 3);
// => 'abc'