Map.prototype.size

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Map 实例的 size 访问器属性返回此映射中的元素数量。

¥The size accessor property of Map instances returns the number of elements in this map.

Try it

描述

¥Description

size 的值是一个整数，表示 Map 对象有多少个条目。size 的设置访问器函数是 undefined；你无法更改此属性。

¥The value of size is an integer representing how many entries the Map object has. A set accessor function for size is undefined; you can not change this property.

示例

¥Examples

使用尺寸

¥Using size

js
const myMap = new Map();
myMap.set("a", "alpha");
myMap.set("b", "beta");
myMap.set("g", "gamma");

console.log(myMap.size); // 3

规范

Specification
ECMAScript Language Specification
# sec-get-map.prototype.size

¥Specifications

浏览器兼容性

BCD tables only load in the browser

¥Browser compatibility

也可以看看

¥See also