Angular2：视图未从Socket.io事件更新

Question

I was simply trying to update my view when I receive an socket event. My code in the component is something like below:

constructor(private _zone: NgZone){
    this.socket = io.connect('http://localhost:3000');
    this.socket.on('someEvent', function(data) {
        this._zone.run(() => {
            this.dataItem = data.item;
            console.log(this.dataItem);
        });
    });
}

when I run this browser console show some errors:

EXCEPTION: TypeError: Cannot read property 'run' of undefined

btw, my socket event are working properly in index.html

Any kind of help is appreciated.

Answer 1

Don't use function () because this way this doesn't point to the current class instance anymore. Use arrow functions instead:

this.socket.on('someEvent', (data) => {