ArrayBuffer.prototype.byteLength
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.
ArrayBuffer 实例的 byteLength 访问器属性返回该数组缓冲区的长度（以字节为单位）。
尝试一下
// Create an ArrayBuffer with a size in bytes
const buffer = new ArrayBuffer(8);
// Use byteLength to check the size
const bytes = buffer.byteLength;
console.log(bytes);
// Expected output: 8
描述
byteLength 属性是一个访问器属性，它的 set 访问器函数是 undefined，这意味着你只能读取这个属性。该值在数组创建时确定，并且无法修改。如果这个 ArrayBuffer 被分离，则此属性返回 0。
示例
使用 byteLength
js
const buffer = new ArrayBuffer(8);
buffer.byteLength; // 8
规范
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-get-arraybuffer.prototype.bytelength |