node/tools/eslint/node_modules/es5-ext/string/is-string.js

'use strict';

var toString = Object.prototype.toString

  , id = toString.call('');

module.exports = function (x) {
	return (typeof x === 'string') || (x && (typeof x === 'object') &&
		((x instanceof String) || (toString.call(x) === id))) || false;
};