RegExp.prototype.toString()

¥Syntax

toString()

¥Parameters

没有任何。

¥None.

¥Return value

表示给定对象的字符串。

¥A string representing the given object.

¥Description

RegExp 对象重写了 Object 对象的 toString() 方法；它不继承 Object.prototype.toString()。对于 RegExp 对象，toString() 方法返回正则表达式的字符串表示形式。

¥The RegExp object overrides the toString() method of the Object object; it does not inherit Object.prototype.toString(). For RegExp objects, the toString() method returns a string representation of the regular expression.

实际上，它读取正则表达式的 source 和 flags 属性并返回 /source/flags 形式的字符串。toString() 返回值保证是可解析的正则表达式文字，尽管它可能与最初为正则表达式指定的文本不完全相同（例如，标志可能会重新排序）。

¥In practice, it reads the regex's source and flags properties and returns a string in the form /source/flags. The toString() return value is guaranteed to be a parsable regex literal, although it may not be the exact same text as what was originally specified for the regex (for example, the flags may be reordered).

¥Examples

¥Using toString()

以下示例显示 RegExp 对象的字符串值：

¥The following example displays the string value of a RegExp object:

const myExp = new RegExp("a+b+c");
console.log(myExp.toString()); // '/a+b+c/'

const foo = new RegExp("bar", "g");
console.log(foo.toString()); // '/bar/g'

¥Empty regular expressions and escaping

由于 toString() 访问 source 属性，空正则表达式返回字符串 "/(?:)/"，并且诸如 \n 之类的行终止符被转义。这使得返回值始终是有效的正则表达式文字。

¥Since toString() accesses the source property, an empty regular expression returns the string "/(?:)/", and line terminators such as \n are escaped. This makes the returned value always a valid regex literal.

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

new RegExp("\n").toString() === "/\\n/"; // true

¥See also

• Object.prototype.toString()