静态方法：Buffer.concat(list[, totalLength])

¥Static method: Buffer.concat(list[, totalLength])

• list <Buffer[]> | <Uint8Array[]> 要连接的 Buffer 或 <Uint8Array> 实例的列表。

  ¥list <Buffer[]> | <Uint8Array[]> List of Buffer or <Uint8Array> instances to concatenate.

• totalLength <integer> 连接时 list 中 Buffer 实例的总长度。

  ¥totalLength <integer> Total length of the Buffer instances in list when concatenated.

• 返回：<Buffer>

  ¥Returns: <Buffer>

返回新的 Buffer，它是将 list 中的所有 Buffer 实例连接在一起的结果。

¥Returns a new Buffer which is the result of concatenating all the Buffer instances in the list together.

如果列表没有条目，或者 totalLength 为 0，则返回新的零长度 Buffer。

¥If the list has no items, or if the totalLength is 0, then a new zero-length Buffer is returned.

如果未提供 totalLength，则从 list 中的 Buffer 实例通过相加其长度来计算。

¥If totalLength is not provided, it is calculated from the Buffer instances in list by adding their lengths.

如果提供了 totalLength，则将其强制为无符号整数。如果 list 中的 Buffer 的组合长度超过 totalLength，则结果将被截断为 totalLength。如果 list 中 Buffer 的总长度小于 totalLength，则剩余空间用零填充。

¥If totalLength is provided, it is coerced to an unsigned integer. If the combined length of the Buffers in list exceeds totalLength, the result is truncated to totalLength. If the combined length of the Buffers in list is less than totalLength, the remaining space is filled with zeros.

import { Buffer } from 'node:buffer';

// Create a single `Buffer` from a list of three `Buffer` instances.

const buf1 = Buffer.alloc(10);
const buf2 = Buffer.alloc(14);
const buf3 = Buffer.alloc(18);
const totalLength = buf1.length + buf2.length + buf3.length;

console.log(totalLength);
// Prints: 42

const bufA = Buffer.concat([buf1, buf2, buf3], totalLength);

console.log(bufA);
// Prints: <Buffer 00 00 00 00 ...>
console.log(bufA.length);
// Prints: 42const { Buffer } = require('node:buffer');

// Create a single `Buffer` from a list of three `Buffer` instances.

const buf1 = Buffer.alloc(10);
const buf2 = Buffer.alloc(14);
const buf3 = Buffer.alloc(18);
const totalLength = buf1.length + buf2.length + buf3.length;

console.log(totalLength);
// Prints: 42

const bufA = Buffer.concat([buf1, buf2, buf3], totalLength);

console.log(bufA);
// Prints: <Buffer 00 00 00 00 ...>
console.log(bufA.length);
// Prints: 42拷贝

Buffer.concat() 也像 Buffer.allocUnsafe() 一样使用内部 Buffer 池。

¥Buffer.concat() may also use the internal Buffer pool like Buffer.allocUnsafe() does.