Using jQuery with Angular-CLI Project

Question

I am using "@angular/cli": "1.0.2" and angular version 4 .

For some reason I had to use jquery based plugin for select area because I couldn't found equivalent plugin in angular.

This is how my component looks like

declare var $ : any;
//adding only necessary code
export class SelectComponent implements OnInit {

    constructor(private _ngZone: NgZone) {}

    public rowData: any = [];

    ngOnInit() {
        $('img#example').selectAreas({
            minSize: [10, 10],
            onChanged: this.debugQtyAreas,
            width: 500,
            areas: [{
                x: 10,
                y: 20,
                width: 60,
                height: 100,
            }]
        });
    }
    debugQtyAreas(event, id, areas) {
        this.rowData = areas.map(function(obj) {
            return {
                left: obj.x,
                top: obj.y,
                id: obj.id
            };
        });
    };
}

Some how this way my jquery thing is working I am able to select areas on a Image.

But the value I am pushing / assigning to array rowData are not updating in the view

I tried searching on internet and found this solution working for everyone but not for me

this._ngZone.run(() => {
      //running code inside this 
})

But I am getting error here as

Cannot read property 'run' of undefined

Same thing happening with rowData, when I tried to push data instead of assigning it from map like following

for(var i = 0; i < areas.length; i++){
    this.rowData.push({
        left: areas[i].x,
        top: areas[i].y,
        id: obj.id
    });
}

It says Cannot read property 'push' of undefined

Answer 1

You need to use bind when you pass a function by reference if you want to persist the this reference.

onChanged: this.debugQtyAreas.bind(this)

When you're writting inline functions with TypeScript don't use the function prefix. If you use the => notation the this reference will persist by default.

    this.rowData = areas.map((obj) => {
        return {
            left: obj.x,
            top: obj.y,
            id: obj.id
        };
    });    

Answer 2

this becomes reserved inside jQuery functions and is not referenced to the global scope as it usually is.

I always add this lines at the top of my function:

let scope = this;

And then use scope instead of this`, eg

scope._ngZone.run(() => {
  //running code inside this 
})

...

for(var i = 0; i < areas.length; i++){
    scope.rowData.push({
        left: areas[i].x,
        top: areas[i].y,
        id: obj.id
    });
}