regExp.@@split

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

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, 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 the separator argument is a RegExp object. 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 split behavior in RegExp subclass.

If the str argument is not a RegExp object, String.prototype.split() doesn't call this method, nor create a RegExp object.

Examples

Direct call

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

var re = /-/g;
var str = '2016-01-02';
var 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) {
    var result = RegExp.prototype[Symbol.split].call(this, str, limit);
    return result.map(x => "(" + x + ")");
  }
}

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

Specifications

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'RegExp.prototype[@@split]' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'RegExp.prototype[@@split]' in that specification.	Draft

Browser compatibility

See also

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