现代浏览器支持BigInt https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt and bigint原始类型，我们可以将它与随机生成的包含 8 个字节的数组组合（的大小bigint是 8 字节（64 位）).
1. 生成随机数BigInt https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt性能明智
我们可以生成一个16个字符长度的随机十六进制字符串并将其直接应用于BigInt https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt:
const hexString = Array(16)
.fill()
.map(() => Math.round(Math.random() * 0xF).toString(16))
.join('');
const randomBigInt = BigInt(`0x${hexString}`);
// randomBigInt will contain a random Bigint
document.querySelector('#generate').addEventListener('click', () => {
const output = [];
let lines = 10;
do {
const hexString = Array(16)
.fill()
.map(() => Math.round(Math.random() * 0xF).toString(16))
.join('');
const number = BigInt(`0x${hexString}`);
output.push(`${
number.toString().padStart(24)
} : 0x${
hexString.padStart(16, '0')
}`);
} while (--lines > 0);
document.querySelector('#numbers').textContent = output.join('\n');
});
<button id="generate">Generate</button>
<pre id="numbers"><pre>
2. 生成随机数BigInt https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt来自随机字节数组
如果我们想使用Uint8Array或者如果我们想要更多地控制位操作，我们可以结合Array.prototype.fill https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill with Array.prototype.map https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map生成一个包含 8 个随机字节数值的数组 (请注意，这比上述方法慢 50% 左右):
const randomBytes = Array(8)
.fill()
.map(() => Math.round(Math.random() * 0xFF));
// randomBytes will contain something similar to this:
// [129, 59, 98, 222, 20, 7, 196, 244]
然后我们使用Array.prototype.reduce https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce初始化一个BigInt https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt零值和左移每个随机字节值位置 X 8 位并申请按位或到每个的当前值reduce迭代：
const randomBigInt = randomBytes
.reduce((n, c, i) => n | BigInt(c) << BigInt(i) * 8n, 0n);
// randomBigInt will contain a random Bigint
生成 10 个随机数的工作示例BigInt values
document.querySelector('#generate').addEventListener('click', () => {
const output = [];
let lines = 10;
do {
const number = Array(8)
.fill()
.map(() => Math.round(Math.random() * 0xFF))
.reduce((n, c, i) => n | BigInt(c) << BigInt(i) * 8n, 0n);
output.push(`${
number.toString().padStart(24)
} : 0x${
number.toString(16).padStart(16, '0')
}`);
} while (--lines > 0);
document.querySelector('#numbers').textContent = output.join('\n');
});
<button id="generate">Generate</button>
<pre id="numbers"><pre>
