尝试一下
// Create an ArrayBuffer with a size in bytes
const buffer = new ArrayBuffer(16);
const view1 = new DataView(buffer);
const view2 = new DataView(buffer, 12, 4); // From byte 12 for the next 4 bytes
console.log(view1.byteLength + view2.byteLength); // 16 + 4
// Expected output: 20
语法
dataview.byteLength
描述
byteLength 属性是一个获取 (accessor) 属性，它的 set 属性为 undefined，这意味着它是只读的。值在 DataView 被创建时就确定了，且不能改变。如果 DataView 没有指定偏移量或 byteLength，那么被引用的 ArrayBuffer 的字节长度将被返回。
Examples
Using the byteLength property
js
var buffer = new ArrayBuffer(8);
var dataview = new DataView(buffer);
dataview.byteLength; // 8 (matches the byteLength of the buffer)
var dataview2 = new DataView(buffer, 1, 5);
dataview2.byteLength; // 5 (as specified when constructing the DataView)
var dataview3 = new DataView(buffer, 2);
dataview3.byteLength; // 6 (due to the offset of the constructed DataView)
规范
| 规范 |
|---|
| ECMAScript® 2027 Language Specification # sec-get-dataview.prototype.bytelength |