shim.js

"use strict";

var value     = require("../../../object/valid-value")
  , toInteger = require("../../../number/to-integer")

  , max = Math.max, min = Math.min;

module.exports = function (searchString/*, position*/) {
	var start, self = String(value(this));
	start = min(max(toInteger(arguments[1]), 0), self.length);
	return self.indexOf(searchString, start) === start;
};