const ab = new ArrayBuffer(32);
const iA = new Int8Array(ab);
iA[0] = 97; //把二进制的数据的首位改为97，97为小写字母a的 ascii 码；
const blob = new Blob([iA], { type: "application/octet-binary" }); //把二进制的码转化为blob类型
const url = URL.createObjectURL(blob);
window.open(url);

// ArrayBuffer -> Blob
const uint8Array = new Uint8Array([1, 2, 3]);
const arrayBuffer = uint8Array.buffer;
const blob = new Blob([arrayBuffer]);

// Blob -> ArrayBuffer
const uint8ArrayNew = null;
const arrayBufferNew = null;
const fileReader = new FileReader();
fileReader.onload = function (event) {
  arrayBufferNew = event.target.result;
  uint8ArrayNew = new Uint8Array(arrayBufferNew);

  // warn if read values are not the same as the original values
  // arrayEqual from: http://stackoverflow.com/questions/3115982/how-to-check-javascript-array-equals
  function arrayEqual(a, b) {
    return !(a < b || b < a);
  }
  if (arrayBufferNew.byteLength !== arrayBuffer.byteLength)
    // should be 3
    console.warn("ArrayBuffer byteLength does not match");
  if (arrayEqual(uint8ArrayNew, uint8Array) !== true)
    // should be [1,2,3]
    console.warn("Uint8Array does not match");
};
fileReader.readAsArrayBuffer(blob);
fileReader.result; // also accessible this way once the blob has been read

// TypedArray
const typedArray = new Int8Array(10);

typedArray[0] = 8;
typedArray[1] = 127;
typedArray[2] = 128;
typedArray[3] = 256;

console.log("typedArray", "   -- ", typedArray);
//Int8Array(10) [8, 127, -128, 0, 0, 0, 0, 0, 0, 0]

// DataView
const arrayBuffer = new ArrayBuffer(8 * 10);

const dataView = new DataView(arrayBuffer);

dataView.setInt8(0, 2);
dataView.setFloat32(8, 65535);

// 从偏移位置开始获取不同数据
dataView.getInt8(0);
// 2
dataView.getFloat32(8);
// 65535

// 普通数组
function arrayFunc() {
  const length = 2e6;
  const array = [];
  const index = 0;

  while (length--) {
    array[index] = 10;
    index++;
  }
}

// dataView
function dataViewFunc() {
  const length = 2e6;
  const arrayBuffer = new ArrayBuffer(length);
  const dataView = new DataView(arrayBuffer);
  const index = 0;

  while (length--) {
    dataView.setInt8(index, 10);
    index++;
  }
}

// typedArray
function typedArrayFunc() {
  const length = 2e6;
  const typedArray = new Int8Array(length);
  const index = 0;

  while (length--) {
    typedArray[index++] = 10;
  }
}