regExp.@@search

The [@@search]() method executes a search for a match between a this regular expression and a string.

Syntax

regexp[Symbol.search](str)

Parameters

str

A String that is a target of the search.

Return value

integer

If successful, [@@search]() returns the index of the first match of the regular expression inside the string. Otherwise, it returns -1.

Description

This method is called internally in String.prototype.search(). For example, the following two examples return the same result.

'abc'.search(/a/);

/a/[Symbol.search]('abc');

This method exists for customizing the search behavior in RegExp subclasses.

Examples

Direct call

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

var re = /-/g;
var str = '2016-01-02';
var result = re[Symbol.search](str);
console.log(result);  // 4

Using @@search in subclasses

Subclass of RegExp can override [@@search]() method to modify the behavior.

class MyRegExp extends RegExp {
  constructor(str) {
    super(str)
    this.pattern = str;
  }
  [Symbol.search](str) {
    return str.indexOf(this.pattern);
  }
}

var re = new MyRegExp('a+b');
var str = 'ab a+b';
var result = str.search(re); // String.prototype.search calls re[@@search].
console.log(result); // 3

Specifications

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

Browser compatibility

See also

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