Update HTML canvas tag on every AJAX request with new data

Question

I want to update my canvas on every AJAX request if new user is found or there is new connection of existing users.

I have users and connections between them:

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Answer 1

I worked from your Source Code Reference Fiddle, which worked pretty ok to me.

Added a couple of things:

First of a seperate function to add a user to the users array. This way, users can easily be added after a successful webservice call.

Second, affffded a couple of helper functions to get random positions and directions.

function addUser(user) {
    users.push({
    id: user.UserId,
    connections: user.Connections,
    width: 80,
    height: 80,
    x: getRandomX(),
    y: getRandomY(),
    dir: {
        x: getDir(),
        y: getDir()
    }
  });
}

// the success callback from your webservice
// guess this receives a `user` object with Id and Connections
// for the test we use `getRandomConnections` 
function getDataFromWebService() {
  let newUser = { "UserId": Date.now(), "Connections": getRandomConnections() };
  addUser(newUser);
}

Fiddle

When you connect your webservice, you can ditch the getRandomConnections function and reference. In your webservice success callback, make sure you have an object in the format:

{ UserId: 1337, Connections: [1, 2] }

Pass that object to the addUser function.