Promise always return "undefined" in Angular 4

Question

I'm trying to pass data using http.get from a JSON to other component, but always I get a "undefined"

In my service.ts I have the getDate function

getData(): Promise<MinnanoNihongo[]>{
   return this.http.get("../../assets/json/leccion1.json")
          .toPromise()
          .then(response => response.json().data as MinnanoNihongo[]);
}

And in my component I call using:

this.MinnaData
         .getData()
         .then( data => this._Minna = data );
    console.log(this._Minna);  //show Undefined in console

I'm new using Angular and typescript so I don't know what produce the problem.

score 1 · Answer 1 · answered Sep 21 '17 at 11:02

1

It's because console.log(this._Minna); is executed before .then( data => this._Minna = data );

Try

this.MinnaData
         .getData()
         .then( data => this._Minna = data ).then(() => {
             console.log(this._Minna)
         });

answered Sep 21 '17 at 11:02

ponury-kostek

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Sajeetharan · Answer 2 · 2017-09-21T02:06:05.640

0

You should print console.log inside then

this.MinnaData
         .getData()
         .then( (data) => {this._Minna = data;
          console.log(this._Minna);
 });

edited Sep 21 '17 at 02:06

answered Sep 21 '17 at 01:35

Sajeetharan

216,225
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this make me an error " ')' expected " – Devjoks Sep 21 '17 at 01:47
@user1553471 check the updated one – Sajeetharan Sep 21 '17 at 02:06
1

now don't show errors, but still showing "undefined" – Devjoks Sep 21 '17 at 02:40

Promise always return "undefined" in Angular 4

2 Answers2