Node WS accessing object data on received message-CodePudding

Following the standard example from the NodeJS 'ws' package: https://www.npmjs.com/package/ws

import WebSocket from 'ws';

const ws = new WebSocket('ws://www.host.com/path');

ws.on('open', function open() {
  ws.send('something');
});

ws.on('message', function message(data) {
  console.log('received: %s', data);
});

I am wondering how to do anything with the data that I receive on the on.('message') method. The returned data looks like it is somehow encoded (Arraybuffered?):

console.log(data) produces: <Buffer 7b 22 6b 65 65 70 41 6c 69 76 65 22 3a 22 31 22 7d>

console.log(data.toString()) produces: {"keepAlive":"1"}

. How do I go about converting this data into an object, where the keys would be accessible? e.g.:

ws.on('message', function message(data) {

  //Some conversion needs to happen here

  if(data.thatKey){
    doThis();
  }
});

.toString()seems to correctly convert the data into a readable string, but this string can't be parsed back into an object. I have also tried JSON.stringify() and then JSON.parse() but this also produces a string that cannot be converted into an object.

I have also tried something like this:

function ab2str(buf) {
        return decoder.decode(new Uint8Array(buf));
}

Which also returns a string that cannot be converted into an object (it seems).

CodePudding user response：

You are getting a string of text (in this case json) and you should var obj = JSON.parse(data)

which in case of your data would look like:

// console.log(data.toString()) produces: {"keepAlive":"1"}
var data = `{"keepAlive":"1"}`;
var obj = JSON.parse(data);
console.log(obj)

CodePudding user response：

For some reason, the data I get from the socket is a UInt8Array. This worked for me:

ws.on('message', function message(data) {
      const newdata = JSON.parse(JSON.stringify(data));
      const enc = new TextDecoder("utf-8");
      const arr = new Uint8Array(newdata.data);
      const decoded = enc.decode(arr);
      const object =  JSON.parse(decoded);
     
      if(object.keepAlive === '1'){
        console.log('success');
      }
    });