如何在打字稿中通过 websocket 接收浮点数据

Question

我知道没有办法像字符串一样轻松地发送和接收浮点数。但是，如果我这样设置我的 websocket：

ws = new WebSocket(address);
ws.binaryType = 'blob';

我应该能够将传入的字节串转换为浮点数。将浮点数转换为字节串并在服务器端发送它们很容易。

我能找到的最接近答案的是this。但是，我发现 e.target.result 是未定义的。我尝试只使用e.target，但编译器抛出了一个我不知道如何修复的类型错误。

还有this之类的问题，将uint数组转换成浮点数。但是如果我有这样的东西

ws.onmessage = function(event){
  //do something with event.data
}

当event.data 不仅仅是像here 这样的字符串时，我需要了解如何使用它。

Answer 1

在适配this answer和this answer之后，我想出了如下解决方案：

//open the socket and set the data type to blob
let socket = new WebSocket(address);
socket.binaryType = 'blob';

//we will store 6 positions at a time
let positions = new Float32Array(18);

//helpers
let buffer = new ArrayBuffer(4);
let view = new DataView(buffer);

//say hello
socket.onopen = function(){
  socket.send('Hello');
};

//keep track of where we are in the position array
let posIndex = 0;

socket.onmessage = function(msg){
  //convert message to Uint8 array
  let bitArray = new Uint8Array(msg.data);
  for(let i = 0; i < 3; i++){
    for(let j = 0; j < 4; j++){
      //set the elements of the DataView equal to the bytes
      view.setUint8(j, bitArray[4*i + j]);
    }

    //update the positions
    if(posIndex < 5){
      positions[3*posIndex + i] = view.getFloat32(0);
      posIndex++;
    }
    else positions[15 + i] = view.getFloat32(0);
  }

  //this should log the positions as they come in
  paragraph.innerHTML = paragraph.innerHTML + ",("
                      + positions[posIndex] + ","
                      + positions[posIndex + 1] + ","
                      + positions[posIndex + 2] + ")";

  //the server won't send another position until it hears from the client
  socket.send('r');
};