function padStart(string, length, chars) {
      string = toString(string);
      length = toInteger(length);

      var strLength = length ? stringSize(string) : 0;
      return (length && strLength < length)
        ? (createPadding(length - strLength, chars) + string)
        : string;
    }
Pads `string` on the left side if it's shorter than `length`. Padding
characters are truncated if they exceed `length`.

@static
@memberOf _
@since 4.0.0
@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

_.padStart('abc', 6);
// => '   abc'

_.padStart('abc', 6, '_-');
// => '_-_abc'

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