String.prototype.endsWith() - JavaScript 编辑

The endsWith() method determines whether a string ends with the characters of a specified string, returning true or false as appropriate.

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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

str.endsWith(searchString[, length])

Parameters

searchString

The characters to be searched for at the end of str.

length Optional

If provided, it is used as the length of str. Defaults to str.length.

Return value

true if the given characters are found at the end of the string; otherwise, false.

Description

This method lets you determine whether or not a string ends with another string. This method is case-sensitive.

Examples

Using endsWith()

let str = 'To be, or not to be, that is the question.'

console.log(str.endsWith('question.'))  // true
console.log(str.endsWith('to be'))      // false
console.log(str.endsWith('to be', 19))  // true

Polyfill

This method has been added to the ECMAScript 6 specification and may not be available in all JavaScript implementations yet. However, you can polyfill String.prototype.endsWith() with the following snippet:

if (!String.prototype.endsWith) {
  String.prototype.endsWith = function(search, this_len) {
    if (this_len === undefined || this_len > this.length) {
      this_len = this.length;
    }
    return this.substring(this_len - search.length, this_len) === search;
  };
}

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'String.prototype.endsWith' in that specification.

Browser compatibility

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See also

• String.prototype.startsWith()
• String.prototype.includes()
• String.prototype.indexOf()
• String.prototype.lastIndexOf()