buf.subarray([start[, end]])

• start <integer> 新的 Buffer 将开始的位置。默认值:0。

  \start <integer> Where the new Buffer will start. Default: 0.

• end <integer> 新的 Buffer 将结束的位置(不包括在内)。默认值:buf.length。

  \end <integer> Where the new Buffer will end (not inclusive). Default: buf.length.

• 返回:<Buffer>

  \Returns: <Buffer>

返回新的 Buffer,其引用与原始缓冲区相同的内存,但由 start 和 end 索引进行偏移和裁剪。

\Returns a new Buffer that references the same memory as the original, but offset and cropped by the start and end indices.

指定 end 大于 buf.length 将返回与 end 等于 buf.length 相同的结果。

\Specifying end greater than buf.length will return the same result as that of end equal to buf.length.

该方法继承自 TypedArray.prototype.subarray()。

\This method is inherited from TypedArray.prototype.subarray().

修改新的 Buffer 切片会修改原来 Buffer 中的内存,因为两个对象分配的内存是重叠的。

\Modifying the new Buffer slice will modify the memory in the original Buffer because the allocated memory of the two objects overlap.

import { Buffer } from 'node:buffer';
// Create a `Buffer` with the ASCII alphabet, take a slice, and modify one byte
// from the original `Buffer`.
const buf1 = Buffer.allocUnsafe(26);
for (let i = 0; i < 26; i++) {
 // 97 is the decimal ASCII value for 'a'.
 buf1[i] = i + 97;
}
const buf2 = buf1.subarray(0, 3);
console.log(buf2.toString('ascii', 0, buf2.length));
// Prints: abc
buf1[0] = 33;
console.log(buf2.toString('ascii', 0, buf2.length));
// Prints: !bcconst { Buffer } = require('node:buffer');
// Create a `Buffer` with the ASCII alphabet, take a slice, and modify one byte
// from the original `Buffer`.
const buf1 = Buffer.allocUnsafe(26);
for (let i = 0; i < 26; i++) {
 // 97 is the decimal ASCII value for 'a'.
 buf1[i] = i + 97;
}
const buf2 = buf1.subarray(0, 3);
console.log(buf2.toString('ascii', 0, buf2.length));
// Prints: abc
buf1[0] = 33;
console.log(buf2.toString('ascii', 0, buf2.length));
// Prints: !bc拷贝

指定负索引会导致相对于 buf 的末尾而不是开头生成切片。

\Specifying negative indexes causes the slice to be generated relative to the end of buf rather than the beginning.

import { Buffer } from 'node:buffer';
const buf = Buffer.from('buffer');
console.log(buf.subarray(-6, -1).toString());
// Prints: buffe
// (Equivalent to buf.subarray(0, 5).)
console.log(buf.subarray(-6, -2).toString());
// Prints: buff
// (Equivalent to buf.subarray(0, 4).)
console.log(buf.subarray(-5, -2).toString());
// Prints: uff
// (Equivalent to buf.subarray(1, 4).)const { Buffer } = require('node:buffer');
const buf = Buffer.from('buffer');
console.log(buf.subarray(-6, -1).toString());
// Prints: buffe
// (Equivalent to buf.subarray(0, 5).)
console.log(buf.subarray(-6, -2).toString());
// Prints: buff
// (Equivalent to buf.subarray(0, 4).)
console.log(buf.subarray(-5, -2).toString());
// Prints: uff
// (Equivalent to buf.subarray(1, 4).)拷贝