How to access array element correctly from JSON in Angular 5 app?

Question

I have the following JSON definition:

export class Company {
  name: string;
  trips : Trip[] = [];
}

I am able to see the trips in the console using:

console.log(this.company);

But I am not able to access the array elements (trip), I've tried the following:

for(let i = 0; i < this.company.trips.length; i++){
        console.log(this.company.trips[i]);      
  }

When I display the company to the log I'm getting the trip as you can see below:

{id: 1}
name: "Sample"
trips: {id: 1, r: "ABC"}
id: 1

Any idea how to access array elements in Angular thanks?

the variable is called trip ... not trips. change the name in the class. trips: Trip[]. Also when console. logging like this it will just show "Object" if you dont specify a property of trips — jcuypers
– jcuypers, Commented Feb 21, 2019 at 7:24
it was a typo, I update the question to "trips" as it should be. — user2304483
– user2304483, Commented Feb 21, 2019 at 7:27
I am curious, how he wrote that code. It will throw error right. — Arun Kumar
– Arun Kumar, Commented Feb 21, 2019 at 7:27
in .ts the array index begings by 0, so for (let i=0;i<this.company.trips.length;i++) -use "let, not var", and begind by 0-. By the way you must sure this.company.trips are not null. You can use trips : Trip[]=[] — Eliseo
– Eliseo, Commented Feb 21, 2019 at 7:33

dev-dan · Accepted Answer · 2019-02-21 10:30:59Z

1

Using a combination of Object.keys() and forEach() will let you iterate through the the object in a similar fashion to an array.

explination

const x = {hello: "hi"};  
console.log(Object.keys(x)); // will return array looking like 

// [hello] which you can run a for each on.

Object.keys(x).forEach(data => {
    console.log(x[data]); // will return `hi`
});

Solution

const trips = {id: 1, r: "ABC"}; // const trips = this.company.trips

if (trips) // check the value exists here 
  {
    Object.keys(trips).forEach((data) => {
    console.log(trips[data]);
  });
}

edited Feb 21, 2019 at 10:30

answered Feb 21, 2019 at 7:50

dev-dan

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3 Comments

user2304483 Over a year ago

Your solution work, I am able to see in the log now: 1 ABC but from some reason it show multiple times, something like 30 times.

dev-dan Over a year ago

Be sure that you only call this function once i would imagine that would be where you are getting an issue.

user2304483 Over a year ago

Your solution works so I'm going to solve this question and open a new one for the duplicate.

Arun Kumar · Accepted Answer · 2019-02-21 07:26:22Z

0

if(this.company)
     this.Company.trips.forEach(x => {
            console.log(x);
        });

answered Feb 21, 2019 at 7:26

Arun Kumar

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3 Comments

user2304483 Over a year ago

I ma getting: ERROR TypeError: this.company.trips.forEach is not a function

user2304483 Over a year ago

Yes it is as you can see in my question.

Arun Kumar Over a year ago

if it is array, you might not get forEach is not an function error. better show your sample response.

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