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JS 参考手册

JS 参考手册(字母排序)

JavaScript

JS Arrays JS Boolean JS Classes JS Dates JS Error JS Global JS Iterators JS JSON JS Maps JS Math JS Numbers JS Objects JS Operators JS Assignment JS Arithmetic JS Comparison JS Logical Operators JS Bitwise Operators JS Misc Operators JS Precedence JS Promises JS RegExp Patterns JS RegExp Reference JS Sets JS Statements JS Strings JS Typed Arrays JS Typed Reference

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<a> <abbr> <address> <area> <article> <aside> <audio> <b> <base> <bdo> <blockquote> <body> <br> <button> <canvas> <caption> <cite> <code> <col> <colgroup> <datalist> <dd> <del> <details> <dfn> <dialog> <div> <dl> <dt> <em> <embed> <fieldset> <figcaption> <figure> <footer> <form> <head> <header> <h1> - <h6> <hr> <html> <i> <iframe> <img> <ins> <input> button <input> checkbox <input> color <input> date <input> datetime <input> datetime-local <input> email <input> file <input> hidden <input> image <input> month <input> number <input> password <input> radio <input> range <input> reset <input> search <input> submit <input> text <input> time <input> url <input> week <kbd> <label> <legend> <li> <link> <map> <mark> <menu> <menuitem> <meta> <meter> <nav> <object> <ol> <optgroup> <option> <output> <p> <param> <pre> <progress> <q> <s> <samp> <script> <section> <select> <small> <source> <span> <strong> <sub> <summary> <sup> <table> <tbody> <td> <tfoot> <th> <thead> <tr> <textarea> <time> <title> <track> <u> <ul> <var> <video>

JavaScript new Map() 方法


示例

通过将数组传递给 new Map() 构造函数来创建 Map 对象:

// 创建一个 Map 映射
const fruits = new Map([
  ["apples", 500],
  ["bananas", 300],
  ["oranges", 200]
]);
亲自试一试 »

Creating a new Map object and add elements with the set() method:

// 创建一个 Map 映射
const fruits = new Map();

// 设置映射值
fruits.set("apples", 500);
fruits.set("bananas", 300);
fruits.set("oranges", 200);
亲自试一试 »

描述

new Map()构造函数创建一个Map对象。


注意

Map 对象只能通过 new Map()

构造。

语法

new Map(iterable)

参数

参数 描述
iterable 可选。
一个包含键值对的可迭代对象。

返回值

类型 描述
Object 一个新的 Map 对象。


浏览器支持

Map 是 ECMAScript 6 (ES6 2015) 的一项特性。

JavaScript 2015 自 2017 年 6 月起,所有浏览器均已支持 JavaScript 2015。

Chrome
51
Edge
15
Firefox
54
Safari
10
Opera
38
2016年5月 2017年4月 2017年6月 2016年9月 2016年6月

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