js ArrayBufferView & TypeArray All In One

js ArrayBufferView & TypeArray All In One

ArrayBuffer / 数组缓冲区

// ✅ > 100000
2**64;
18446744073709552000

// ✅ > 100000
2**32;
4294967296

// ❌ 太小了 < 100000
2**16;
65536

// ❌ 太小了 < 100000
2**8;
256

// Uint8Array 要受到 TypedArray  限制 2  **  8 ❌
new Uint8Array(1000).map((item, i) => i + 1)

[...new Uint8Array(100000)].map((item, i) => i + 1)

[...new Uint16Array(1000000)].map((item, i) => i + 1)

[...new Uint32Array(1000000)].map((item, i) => i + 1)

// ...spread 数组展开后，转变成普通的数组，突破了 TypedArray  的限制  2  **  8  ✅

[...new Uint8Array(1000)].map((item, i) => i + 1)

TypedArray

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

Uint8Array

js no for 100 array

const arr = new Uint8Array(100).map((item, i) => i);
 

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array

Uint32Array

js 数组里面有10万个数据，取第 1 个元素和第 10 万个元素的时间相差多少?

const arr = (new Uint32Array(100000)).map((item, i) => i +  1);

function testPerformance(arr, i) {
  let startTime = performance.now();
  console.log(`arr[i], i =`, arr[i], i);
  let endTime = performance.now();
  console.log(`🚀performance time is \`${endTime - startTime}\` ms`);
}

function testTime(arr, i) {
  console.time('array test');
  console.log(`arr[i], i =`, arr[i], i);
  console.timeEnd('array test');
}

testPerformance(arr, 0);
testPerformance(arr, 99999);

console.log('\n');

testTime(arr, 0);
testTime(arr, 99999);

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array

BigUint64Array

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array

refs

https://www.cnblogs.com/xgqfrms/p/8982974.html

https://www.cnblogs.com/xgqfrms/p/16714232.html

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