静态方法:Buffer.byteLength(string[, encoding])

\Static method: Buffer.byteLength(string[, encoding])

• string <string> | <Buffer> | <TypedArray> | <DataView> | <ArrayBuffer> | <SharedArrayBuffer> 用于计算长度的值。

  \string <string> | <Buffer> | <TypedArray> | <DataView> | <ArrayBuffer> | <SharedArrayBuffer> A value to calculate the length of.

• encoding <string> 如果 string 是字符串,则这就是它的编码。默认值:'utf8'。

  \encoding <string> If string is a string, this is its encoding. Default: 'utf8'.

• 返回:<integer> string 中包含的字节数。

  \Returns: <integer> The number of bytes contained within string.

使用 encoding 编码时返回字符串的字节长度。这与 String.prototype.length 不同,String.prototype.length 不考虑用于将字符串转换为字节的编码。

\Returns the byte length of a string when encoded using encoding. This is not the same as String.prototype.length, which does not account for the encoding that is used to convert the string into bytes.

对于 'base64'、'base64url' 和 'hex',此函数假定输入有效。对于包含非 base64/hex 编码数据(例如空格)的字符串,返回值可能大于从字符串创建的 Buffer 的长度。

\For 'base64', 'base64url', and 'hex', this function assumes valid input. For strings that contain non-base64/hex-encoded data (e.g. whitespace), the return value might be greater than the length of a Buffer created from the string.

import { Buffer } from 'node:buffer';
const str = '\u00bd + \u00bc = \u00be';
console.log(`${str}: ${str.length} characters, ` +
 `${Buffer.byteLength(str, 'utf8')} bytes`);
// Prints: 1⁄2 + 1⁄4 = 3⁄4: 9 characters, 12 bytesconst { Buffer } = require('node:buffer');
const str = '\u00bd + \u00bc = \u00be';
console.log(`${str}: ${str.length} characters, ` +
 `${Buffer.byteLength(str, 'utf8')} bytes`);
// Prints: 1⁄2 + 1⁄4 = 3⁄4: 9 characters, 12 bytes拷贝

当 string 为 Buffer/DataView/TypedArray/ArrayBuffer/SharedArrayBuffer 时,返回 .byteLength 报告的字节长度。

\When string is a Buffer/DataView/TypedArray/ArrayBuffer/ SharedArrayBuffer, the byte length as reported by .byteLength is returned.