buf.write(string[, offset[, length]][, encoding])

• string <string> 要写入 buf 的字符串。

  ¥string <string> String to write to buf.

• offset <integer> 开始写入 string 之前要跳过的字节数。默认值：0。

  ¥offset <integer> Number of bytes to skip before starting to write string. Default: 0.

• length <integer> 要写入的最大字节数（写入的字节数不会超过 buf.length - offset）。默认值：buf.length - offset。

  ¥length <integer> Maximum number of bytes to write (written bytes will not exceed buf.length - offset). Default: buf.length - offset.

• encoding <string> string 的字符编码。默认值：'utf8'。

  ¥encoding <string> The character encoding of string. Default: 'utf8'.

• 返回：<integer> 写入的字节数。

  ¥Returns: <integer> Number of bytes written.

根据 encoding 中的字符编码将 string 写入 buf 的 offset 处。length 参数是要写入的字节数。如果 buf 没有足够的空间来容纳整个字符串，则只会写入 string 的一部分。但是，不会写入部分编码的字符。

¥Writes string to buf at offset according to the character encoding in encoding. The length parameter is the number of bytes to write. If buf did not contain enough space to fit the entire string, only part of string will be written. However, partially encoded characters will not be written.

import { Buffer } from 'node:buffer';

const buf = Buffer.alloc(256);

const len = buf.write('\u00bd + \u00bc = \u00be', 0);

console.log(`${len} bytes: ${buf.toString('utf8', 0, len)}`);
// Prints: 12 bytes: ½ + ¼ = ¾

const buffer = Buffer.alloc(10);

const length = buffer.write('abcd', 8);

console.log(`${length} bytes: ${buffer.toString('utf8', 8, 10)}`);
// Prints: 2 bytes : abconst { Buffer } = require('node:buffer');

const buf = Buffer.alloc(256);

const len = buf.write('\u00bd + \u00bc = \u00be', 0);

console.log(`${len} bytes: ${buf.toString('utf8', 0, len)}`);
// Prints: 12 bytes: ½ + ¼ = ¾

const buffer = Buffer.alloc(10);

const length = buffer.write('abcd', 8);

console.log(`${length} bytes: ${buffer.toString('utf8', 8, 10)}`);
// Prints: 2 bytes : ab拷贝