在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

WebAssembly.Memory() 构造函数创建新 Memory object whose buffer property is a resizable ArrayBuffer or SharedArrayBuffer that holds the raw bytes of memory accessed by a WebAssembly Instance .

A memory created by JavaScript or in WebAssembly code will be accessible and mutable from both JavaScript and WebAssembly.

句法

new WebAssembly.Memory(memoryDescriptor);
					

参数

memoryDescriptor

An object that can contain the following members:

initial

The initial size of the WebAssembly Memory, in units of WebAssembly pages.

maximum 可选

The maximum size the WebAssembly Memory is allowed to grow to, in units of WebAssembly pages. When present, the maximum parameter acts as a hint to the engine to reserve memory up front. However, the engine may ignore or clamp this reservation request. Unshared WebAssembly memories don't need to set a maximum , but shared memories do.

shared 可选

A boolean value that defines whether the memory is a shared memory or not. If set to true , it is a shared memory. The default is false .

注意 : A WebAssembly page has a constant size of 65,536 bytes, i.e., 64KiB.

异常

• 若 memoryDescriptor is not of type object, a TypeError is thrown.
• 若 maximum is specified and is smaller than initial ， RangeError is thrown.

范例

Creating a new Memory instance

There are two ways to get a WebAssembly.Memory object. The first way is to construct it from JavaScript. The following example creates a new WebAssembly Memory instance with an initial size of 10 pages (640KiB), and a maximum size of 100 pages (6.4MiB). Its buffer property will return an ArrayBuffer .

var memory = new WebAssembly.Memory({initial:10, maximum:100});
								

The second way to get a WebAssembly.Memory object is to have it exported by a WebAssembly module. The following example (see memory.html on GitHub, and view it live also ) fetches and instantiates the loaded memory.wasm byte code using the WebAssembly.instantiateStreaming() method, while importing the memory created in the line above. It then stores some values in that memory, then exports a function and uses it to sum some values.

WebAssembly.instantiateStreaming(fetch('memory.wasm'), { js: { mem: memory } })
.then(obj => {
  var i32 = new Uint32Array(memory.buffer);
  for (var i = 0; i < 10; i++) {
    i32[i] = i;
  }
  var sum = obj.instance.exports.accumulate(0, 10);
  console.log(sum);
});
								

Creating a shared memory

By default, WebAssembly memories are unshared. You can create a shared memory by passing shared: true in the constructor's initialization object:

let memory = new WebAssembly.Memory({initial:10, maximum:100, shared:true});
								

This memory's buffer property will return a SharedArrayBuffer .

规范

规范
WebAssembly JavaScript 接口 The definition of 'Memory' in that specification.

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
Memory() 构造函数	Chrome 57	Edge 16	Firefox 52 52 Disabled in the Firefox 52 Extended Support Release (ESR).	IE No	Opera 44	Safari 11	WebView Android 57	Chrome Android 57	Firefox Android 52 52 Disabled in the Firefox 52 Extended Support Release (ESR).	Opera Android 43	Safari iOS 11	Samsung Internet Android 7.0	nodejs 8.0.0
shared flag	Chrome 74	Edge 79	Firefox 78	IE No	Opera 62	Safari No	WebView Android No	Chrome Android No	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android No	nodejs 12.0.0

图例

完整支持

完整支持

不支持

不支持

见实现注意事项。

另请参阅

• WebAssembly 概述页面
• WebAssembly 概念
• 使用 WebAssembly JavaScript API

元数据

• 最后修改： Jul 8, 2020

相关话题

1. 标准内置对象
2. WebAssembly
3. 方法
   1. WebAssembly.compile()
   2. WebAssembly.compileStreaming()
   3. WebAssembly.instantiate()
   4. WebAssembly.instantiateStreaming()
   5. WebAssembly.validate()
4. 相关页面：
5. WebAssembly.Module
6. WebAssembly.Global
7. WebAssembly.Instance
8. WebAssembly.Memory
9. WebAssembly.Table
10. WebAssembly.CompileError
11. WebAssembly.LinkError
12. WebAssembly.RuntimeError
13. 继承：
14. Object
15. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
16. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()