Angular 2 build objects from http get request

Question

I've start learning angular 2. I try to get some data via http get request and then I would like to build objects with that data so I can display them with template later. If I am thinking with the wrong way you can tell me.

I have my model AnalyticsData:

export class AnalyticsData {
     pagePath: string;
     pageViews: number;
     uniquePageViews: number;
     avgTimeOnPage: number;
     entrances: number;
     bounceRate: number;

    constructor(object?: any) {
        this.pagePath = object && object.pagePath || null;
        this.pageViews = object && object.pageViews || null;
        this.uniquePageViews = object && object.uniquePageViews || null;
        this.avgTimeOnPage = object && object.avgTimeOnPage || null;
        this.entrances = object && object.entrances || null;
        this.bounceRate = object && object.bounceRate || null;
    }

}

My DataService:

export class DataService {

    private dataUrl: string = 'http://example.com/app/analyticsdata';
    constructor(private http: Http) { }

    getData() {
        return this.http.get(this.dataUrl)
            .map((response: Response) => response.json());
    }

}

My AnalyticsComponent:

export class AnalyticsComponent implements OnInit {

    myData: Array<AnalyticsData>;

    constructor(private services: DataService) { }

    ngOnInit(): void {
        this.getData();
    }

    getData() {
        this.services.getData()
            .subscribe(
            function (response) {
                response.forEach((element: AnalyticsData, index: number) => {
                    this.myData.push(
                        new AnalyticsData({
                            pagePath: element['ga:pagePath'],
                            pageViews: element.pageViews,
                            uniquePageViews: element.uniquePageViews,
                            avgTimeOnPage: element.avgTimeOnPage,
                            entrances: element.entrances,
                            bounceRate: element.bounceRate
                        })
                    );
                });
            },
            function (error) { console.log("Error happened" + error) },
            function () {
                console.log("the subscription is completed");
            }
            );

    }

}

The error with the above is: EXCEPTION: Cannot read property 'push' of undefined. I don't understand why this happened because I've assign the variable myData on the top of the class.

Add this to your constructor and try again: this.MyData = []; — Harry Ninh
– Harry Ninh, Commented Oct 11, 2016 at 5:54
@HarryNinh Thank you I combine your answer with micronyks answer to solve my problem. — amrfs
– amrfs, Commented Oct 11, 2016 at 6:15

micronyks · Accepted Answer · 2016-10-11 05:56:32Z

1

Also use arrowFunction ()=> as shown below,

getData() {
        this.services.getData()
            .subscribe(
            (response) => {                                       //<<<<===here
                response.forEach((element: AnalyticsData, index: number) => {
                    this.myData.push(
                        new AnalyticsData({
                            pagePath: element['ga:pagePath'],
                            pageViews: element.pageViews,
                            uniquePageViews: element.uniquePageViews,
                            avgTimeOnPage: element.avgTimeOnPage,
                            entrances: element.entrances,
                            bounceRate: element.bounceRate
                        })
                    );
                });
            },
            (error) => { console.log("Error happened" + error) }, //<<<===here
            () => {                                               //<<<===here
                console.log("the subscription is completed");
            }
            );

    }

answered Oct 11, 2016 at 5:56

micronyks

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1 Comment

amrfs Over a year ago

Thank you. I also need to put the this.myData = []; in contractor as @HarryNinh say

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