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

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

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

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
ECMAScript (ECMA-262) The definition of 'RegExp.prototype[@@search]' in that specification.

Browser compatibility

BCD tables only load in the browser

See also

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