CODEWITHSUNDEEP
javascriptangulartypescript
Alice
Alice

Reputation: 43

Function does not return anything

import { Injectable } from '@angular/core';

export class Test {
  public id: number; public name: string; public fid: number
};

export const TESTS: Test[] = [
  {id: 1, name: 'Cat', fid: 1},
  {id: 2, name: 'Dog', fid: 1},
  {id: 3, name: 'Elephant', fid: 1},
  {id: 4, name: 'Bird', fid: 1},
  {id: 5, name: 'Duck', fid: 2},
  {id: 6, name: 'Snake', fid: 2},
  {id: 7, name: 'Rabbit', fid: 2},
  {id: 8, name: 'Dolphin', fid: 2},
  {id: 9, name: 'Sheep', fid: 3},
  {id: 10, name: 'Cow', fid: 3},
  {id: 11, name: 'Fish', fid: 3},
  {id: 12, name: 'Monkey', fid: 3}];

let testsPromise = Promise.resolve(TESTS);

@Injectable()
export class TestService {
  getTests(id) { 
    let items: Test[] = [];
    for(var i = 0; i < TESTS.length; i++) {
        if(TESTS[i].fid == id) { 
        items.push(TESTS[i]) 
        }
    }
    return items;
 }
}

It seems that TESTS is unreachable in funciton getTests(id), but testsPromise is available because i receive all data if do return testsPromise in getTests function. Why?

Upvotes: 0

Views: 110

Answers (2)

rodrigocfd
rodrigocfd

Reputation: 8053

Is Test an interface like this?

interface Test {
    id: number;
    name: string;
    fid: number;
}

If so, you must initialize items array before the loop begins (note the use of let):

getTests(id: number) {
    let items: Test[] = [];
    // ...
}

Then, make sure that TESTS, wherever it is declared, is available within the function:

getTests(id: number) {
    console.log(TESTS); // do you see this output?
    // ...
}

With the above set, your code worked fine for me.

Bonus: if you want further refinement, you can rewrite your function in one line:

getTests(id: number): Test[] {
    return TESTS.filter((oneTest: Test) => oneTest.fid === id);
}

Upvotes: 2

Eran Shabi
Eran Shabi

Reputation: 14979

You need to initialize items:

  var items: Test[] = [];

Upvotes: 5

Related Questions