梁美英 / programming · Files

'use strict';

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

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

module.exports = function (searchString/*, endPosition*/) {
	var self, start, endPos;
	self = String(value(this));
	searchString = String(searchString);
	endPos = arguments[1];
	start = ((endPos == null) ? self.length :
			min(max(toInteger(endPos), 0), self.length)) - searchString.length;
	return (start < 0) ? false : (self.indexOf(searchString, start) === start);
};