RegExp.prototype[@@split]() - JavaScript 编辑

The [@@split]() method splits a String object into an array of strings by separating the string into substrings.

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Syntax

regexp[Symbol.split](str[, limit])

Parameters

str

The target of the split operation.

limit Optional

Integer specifying a limit on the number of splits to be found. The [@@split]() method still splits on every match of this RegExp pattern (or, in the Syntax above, regexp), until the number of split items match the limit or the string falls short of this pattern.

Return value

An Array containing substrings as its elements.

Description

This method is called internally in String.prototype.split() if its separator argument is an object that has a @@split method, such as a RegExp. For example, the following two examples return the same result.

'a-b-c'.split(/-/);

/-/[Symbol.split]('a-b-c');

This method exists for customizing the behavior of split() in RegExp subclass.

Examples

Direct call

This method can be used in almost the same way as String.prototype.split(), except the different this and the different order of arguments.

let re = /-/g;
let str = '2016-01-02';
let result = re[Symbol.split](str);
console.log(result);  // ["2016", "01", "02"]

Using @@split in subclasses

Subclasses of RegExp can override the [@@split]() method to modify the default behavior.

class MyRegExp extends RegExp {
  [Symbol.split](str, limit) {
    let result = RegExp.prototype[Symbol.split].call(this, str, limit);
    return result.map(x => "(" + x + ")");
  }
}

let re = new MyRegExp('-');
let str = '2016-01-02';
let result = str.split(re); // String.prototype.split calls re[@@split].
console.log(result); // ["(2016)", "(01)", "(02)"]

Specifications

Browser compatibility

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See also

• String.prototype.split()
• RegExp.prototype[@@match]()
• RegExp.prototype[@@replace]()
• RegExp.prototype[@@search]()
• RegExp.prototype.exec()
• RegExp.prototype.test()