如何通过套接字io发送对象数组？

Question

I have been encountering a problem in sending array of object through socket io

My server side code

var addEntity = function(ent) {
    entityBag.push(ent);
};  
var entityBag = [];
addEntity(new Circle({
            x:  Math.random() * 5000,//(i%20) * space,
            y:  Math.random() * 5000,//Math.floor(i/20)*space,
            color: ['red', 'blue', 'green', 'yellow', 'purple', 'brown', 'violet'][Math.floor(Math.random()*7)],
            droplet: true  
        }));
socket.emit('updatePos',entityBag);

and my client side code

var entityBag = [];
socket.on('updatePos', function(msg) {
    entityBag = msg;
});  

So my when I tried to debug the issue all the objects in the array were empty in the client side code. So I am probably guessing the error is with the socket

please excuse my ignorance if the question is too trivial

The Cirlce class

function Circle(attr) {
    attr = attr    
    var x = attr.x;
    var y = attr.y;
    var color = attr.color ;
    var borderColor = attr.borderColor || 'black';
    var droplet  = attr.droplet ;
}

Answer 1

I can't see your whole code so I can't find bugs in it but I tried to write something similar:

server.js:

'use strict';
const io = require('socket.io')(3000);
var entityBag = []; 
var someObject = {
            x:  Math.random() * 5000,//(i%20) * space,
            y:  Math.random() * 5000,//Math.floor(i/20)*space,
            color: ['red', 'blue', 'green', 'yellow', 'purple', 'brown', 'violet'][Math.floor(Math.random()*7)],
            droplet: true
} 
var anotherObject = {
            name: 'Utsav Mangal',
            color: ['red', 'blue', 'green', 'yellow', 'purple', 'brown', 'violet'],
            human: true,
            somekey: 'foo'
} 
var addEntity = function(ent) {
    entityBag.push(ent);
};             
addEntity(someObject);
addEntity(anotherObject);
io.on('connection', function (socket) {
    socket.emit('updatePos', entityBag);    
});
console.log('Plain socket.io server started at port 3000');

client.js

'use strict';
const socket = require('socket.io-client')('http://localhost:3000');
socket.on('updatePos', function(data) {
    console.log(data);
});

You can try it with node server to start the server and node client to connect to it, everything works fine. You don't have to JSON.stringify/parse, socket.io will do it for you. Your bug is somewhere else. Please show us the whole code.