Constructor array of objects - Typescript

Question

I am using typescript to code in Angular2. I have this object:

export class Car{
    name: String;
    door: {
        position: String;
        id: Number;
    };
}

I have initialized the object following this steps:

constructor() {
    this.door= new Door();
}
export class Door{
    position: String;
    ID: Number
}

and it perfectly works. My problem begins when I try to initialize an array of objects

export class Car{
    name: String;
    door: {
        position: String;
        id: Number;
    };
    color: {
       one: String;
       two: String;

    }[]
}

and I try to do the same Edited

constructor() {
    for (var i = 0; i < 10; i++) {
        this.color.push(new Color);
    }
        this.door= new Door();
    }


export class Color{
    one: String;
    two: String;
}

The error is the following:

ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'push' of undefined TypeError: Cannot read property 'push' of undefined

If you want to add the new Color object to the array, you can do: this.color.push(new Color());. Note: color may not be the ideal name for an array. :-) — Martin Parenteau
– Martin Parenteau, Commented Jan 17, 2018 at 15:51
My problem is that when I try to access like this.car.color[0].one = "white", it says that it is undefined. I guess that I need to initialize the object previously and that is what I am trying to do — bellotas
– bellotas, Commented Jan 17, 2018 at 15:54
@ConnorsFan Actually its not an array it's a tuple type { one: String; two: String; }[] is an array — Titian Cernicova-Dragomir
– Titian Cernicova-Dragomir, Commented Jan 17, 2018 at 15:55

Titian Cernicova-Dragomir · Accepted Answer · 2018-01-17 18:18:32Z

2

The problem is that you declare the color property as tuple with a single item of type {one: string; two: string}

To initialize the tuple you can use

this.color= [new Color()];

Or if you want to declare an array of the type you can use:

color: {
    one: String;
    two: String;
}[]

and initialize it with an empty array:

this.color= [];
// Push 10 elements in the array, you can replace 10 with how many elements you need.
for(let i = 0; i< 10; i++) this.color.push(new Color());

More information about tuples here

edited Jan 17, 2018 at 18:18

answered Jan 17, 2018 at 15:53

Titian Cernicova-Dragomir

253k37 gold badges464 silver badges394 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

bellotas Over a year ago

At the end it solved the problem just for the first position of the array/tuple but when I try to access to the 2nd one it crash

Titian Cernicova-Dragomir Over a year ago

Well the tuple you defined only has one element in theory. If you want an array use the second suggestion in my answer, and initialize with an empty array, and then push as may values in it as you want : ex, adding two elements: this.color= []; this.color.push(new Color(), new Color())

bellotas Over a year ago

ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'push' of undefined

bellotas Over a year ago

I m gonna edit the question so maybe will be more clear

Titian Cernicova-Dragomir Over a year ago

You haven't initialized the array this.color= []; before the for

Collectives™ on Stack Overflow

Constructor array of objects - Typescript

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related