How to add item to list in vue.js

Question

I'm new to vue.js and here is my problem:

data: {
        ws: null, 
        newMsg: '',
        username: null,    
        usersList: '' 
    },
        created: function() {
        var self = this;
        this.ws = new WebSocket('ws://' + window.location.host + '/room');
        this.ws.addEventListener('message', function(e) {
            var msg = JSON.parse(e.data);
                if (msg.Message == "joined" ) {
                self.usersList.push(msg.Name); // <--Problem here 
              }


        });
    },

But I get this error in the browser console:

Uncaught TypeError: self.usersList.push is not a function

I've also tryied a fixed string instead of msg.Name but get the same error.

What's wrong here and how to fix it?

You declared as string usersList: '' in data, change it to usersList: []. — Mat J
– Mat J, Commented Mar 13, 2017 at 4:57
@MatJ Right. Just figured out! Please answer and I'll accept. — Karlom
– Karlom, Commented Mar 13, 2017 at 4:58

toimc · Accepted Answer · 2017-03-13 05:16:15Z

3

1.Use userList:[] as array, that you can use the push() method, see here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push

2.When your e.data is a array, like: [1,2,3,4], you can use concat to combine two array.

var arr1 = [1,2,3,4];
var arr2 = [5,6,7];
var arr = arr1.concat(arr2); // [1, 2, 3, 4, 5, 6, 7]

Or, Array.prototype.push.apply(arr1, arr2); to push all elements from a second array.

var arr1 = [1,2,3,4];
var arr2 = [5,6,7];
Array.prototype.push.apply(arr1, arr2);
console.log(arr1);//[1, 2, 3, 4, 5, 6, 7]

edited Mar 13, 2017 at 5:16

answered Mar 13, 2017 at 5:11

toimc

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