从JavaScript对象中获取数组

Question

I try to get messages from a Server via Websocket and this works so far. I get back an Javascript Object and want to filter out the data I need to put it into the state of my react app.

this is the code im using at the moment:

connection.onmessage = function (newMessage) {

        if(newMessage.data == '{"msg":"ping"}' ){
            connection.send('{"msg": "pong"}')
        }

        newMessage = JSON.parse(newMessage.data)
        console.log(newMessage.fields)       
    }

and this is the object I get back:

Javascript Object

I need the Array at args/0 how do i get it?

Thank You

Answer 1

you can access the 'args' data in the json object like 'newMessage.args'

 var newMessage = {eventName: 'aname', args: ['data1','data2'] } document.getElementById('output').innerHTML = newMessage.args 

 <div id='output'></div> 

Answer 2

It's probably not a good idea to rewrite newMessage in your connection.onmessage function, and may be add more logs when you get a new message. Can you try this version ?

connection.onmessage = function (newMessage) {
    console.log("Received new message :", newMessage.data);

    if(newMessage.data == '{"msg":"ping"}' ){
        connection.send('{"msg": "pong"}')
    }

    var parsedMessage = JSON.parse(newMessage.data);

    if (parsedMessage.msg === "changed") {
        console.log("Received changed message :", parsedMessage.fields.args); 
    }
}

Hope this helps!