crypto.randomFill(buffer[, offset][, size], callback)

• buffer <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> 必须提供。所提供的 buffer 大小不得超过 2**31 - 1。
• offset <number> 默认值： 0
• size <number> 默认值： buffer.length - offset。size 不得超过 2**31 - 1。
• callback <Function> function(err, buf) {}。

此函数类似于 crypto.randomBytes()，但要求第一个参数是将被填充的 Buffer。它还要求传入回调函数。

【This function is similar to crypto.randomBytes() but requires the first argument to be a Buffer that will be filled. It also requires that a callback is passed in.】

如果未提供 callback 函数，将会抛出错误。

【If the callback function is not provided, an error will be thrown.】

import { Buffer } from 'node:buffer';
const { randomFill } = await import('node:crypto');

const buf = Buffer.alloc(10);
randomFill(buf, (err, buf) => {
  if (err) throw err;
  console.log(buf.toString('hex'));
});

randomFill(buf, 5, (err, buf) => {
  if (err) throw err;
  console.log(buf.toString('hex'));
});

// The above is equivalent to the following:
randomFill(buf, 5, 5, (err, buf) => {
  if (err) throw err;
  console.log(buf.toString('hex'));
});const { randomFill } = require('node:crypto');
const { Buffer } = require('node:buffer');

const buf = Buffer.alloc(10);
randomFill(buf, (err, buf) => {
  if (err) throw err;
  console.log(buf.toString('hex'));
});

randomFill(buf, 5, (err, buf) => {
  if (err) throw err;
  console.log(buf.toString('hex'));
});

// The above is equivalent to the following:
randomFill(buf, 5, 5, (err, buf) => {
  if (err) throw err;
  console.log(buf.toString('hex'));
});拷贝

任何 ArrayBuffer、TypedArray 或 DataView 实例都可以作为 buffer 传递。

【Any ArrayBuffer, TypedArray, or DataView instance may be passed as buffer.】

虽然这包括 Float32Array 和 Float64Array 的例子，但不应使用此函数来生成随机浮点数。结果可能包含 +Infinity、-Infinity 和 NaN，即使数组仅包含有限数，它们也不是从均匀随机分布中生成的，并且没有有意义的下限或上限。

【While this includes instances of Float32Array and Float64Array, this function should not be used to generate random floating-point numbers. The result may contain +Infinity, -Infinity, and NaN, and even if the array contains finite numbers only, they are not drawn from a uniform random distribution and have no meaningful lower or upper bounds.】

import { Buffer } from 'node:buffer';
const { randomFill } = await import('node:crypto');

const a = new Uint32Array(10);
randomFill(a, (err, buf) => {
  if (err) throw err;
  console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
    .toString('hex'));
});

const b = new DataView(new ArrayBuffer(10));
randomFill(b, (err, buf) => {
  if (err) throw err;
  console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
    .toString('hex'));
});

const c = new ArrayBuffer(10);
randomFill(c, (err, buf) => {
  if (err) throw err;
  console.log(Buffer.from(buf).toString('hex'));
});const { randomFill } = require('node:crypto');
const { Buffer } = require('node:buffer');

const a = new Uint32Array(10);
randomFill(a, (err, buf) => {
  if (err) throw err;
  console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
    .toString('hex'));
});

const b = new DataView(new ArrayBuffer(10));
randomFill(b, (err, buf) => {
  if (err) throw err;
  console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
    .toString('hex'));
});

const c = new ArrayBuffer(10);
randomFill(c, (err, buf) => {
  if (err) throw err;
  console.log(Buffer.from(buf).toString('hex'));
});拷贝

该 API 使用 libuv 的线程池，这可能对某些应用产生意想不到的负面性能影响；更多信息请参阅 UV_THREADPOOL_SIZE 文档。

【This API uses libuv's threadpool, which can have surprising and negative performance implications for some applications; see the UV_THREADPOOL_SIZE documentation for more information.】

crypto.randomFill() 的异步版本是在单个线程池请求中执行的。为了尽量减少线程池任务时长的差异，在作为完成客户端请求的一部分时，应将大型的 randomFill 请求进行分割。

【The asynchronous version of crypto.randomFill() is carried out in a single threadpool request. To minimize threadpool task length variation, partition large randomFill requests when doing so as part of fulfilling a client request.】