regExp.toString

toString()返回一个表示该正则表达式的字符串。

语法

regexObj.toString(

返回值

代表给定对象的字符串。

描述

RegExp对象覆盖了 Object对象的toString()方法，并没有继承Object.prototype.toString()。对于 RegExp对象，toString方法返回一个该正则表达式的字符串形式。

示例

使用toString()

下例输出 RegExp对象的字符串值：

var myExp = new RegExp('a+b+c'
console.log(myExp.toString()  // logs '/a+b+c/'

var foo = new RegExp('bar', 'g'
console.log(foo.toString()    // logs '/bar/g'

清空正则表达式并转义

从ECMAScript 5开始，一个空的正则表达式返回字符串“/（？：）/”和行结束符如“\ n”被转义：

new RegExp().toString( // "/(?:)/"

new RegExp('\n').toString() === '/\n/';  // true, prior to ES5
new RegExp('\n').toString() === '/\\n/'; // true, starting with ES5

规范

Specification	Status	Comment
ECMAScript 3rd Edition (ECMA-262)	Standard	Initial definition. Implemented in JavaScript 1.1.
ECMAScript 5.1 (ECMA-262)The definition of 'RegExp.prototype.toString' in that specification.	Standard	Added definition for escaping behavior and "(?:)" for empty regular expressions.
ECMAScript 2015 (6th Edition, ECMA-262)The definition of 'RegExp.prototype.toString' in that specification.	Standard
ECMAScript Latest Draft (ECMA-262)The definition of 'RegExp.prototype.toString' in that specification.	Draft

浏览器兼容性

Feature	Chrome	Edge	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)
Escaping	(Yes)	?	38 (38)	(Yes)	(Yes)	(Yes)
Generic function	?	?	39 (39)	?	?	?

Feature	Android	Chrome for Android	Edge	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)
Escaping	(Yes)	(Yes)	?	38.0 (38)	(Yes)	(Yes)	(Yes)
Generic function	?	?	?	39.0 (39)	?	?	?