Typescript Array

Question

I have this Array

numbers1: any=[
               { lat: 43.477254, lng: -3.780953 },
               { lat: 43.472739, lng: -3.781039 },
               { lat: 43.472498, lng: -3.780164 },
               { lat: 43.472023, lng: -3.780363 }
              ];

I want to fill that array dynamically, and I got it in this way:

list:any[]=[];

polygon(event){
   this.list = [event.coords.lat, event.coords.lng];
   this.number.push(this.list);}

But how can I set the values using the structure of Array number1?

{ lat: value, lng: value },

I've tried it but I have not got it. And Sorry by the way, im new on this.

You can leverage Typescript's strengths better if you use more specific types than any. For example, for that array of lat/lng coordinates, you might create a simple Coord class with lat and lng properties, then declare numbers to have the type Coord[]. — John Ellmore
– John Ellmore, Commented Apr 27, 2018 at 17:29
What's the intent between this.numbers, this.list, and this.number? — Aaron Beall
– Aaron Beall, Commented Apr 27, 2018 at 17:41

Kevin Boucher · Accepted Answer · 2018-04-27 17:39:27Z

3

I think you want to push an object, instead of an array:

this.list = {
    lat: event.coords.lat,
    lng: event.coords.lng
};

this.number.push(this.list);

edited Apr 27, 2018 at 17:39

answered Apr 27, 2018 at 17:27

Kevin Boucher

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Comments

Umer Farooq · Accepted Answer · 2018-04-27 17:31:49Z

0

You are trying to push an array rather then an object. And above you have an array named numbers1 and you are pushing in number. Use the correct one

Try this:

list:any={};

polygon(event)
{
   this.list = {lat: event.coords.lat, lng: event.coords.lng};
   this.number.push(this.list);
}

answered Apr 27, 2018 at 17:31

Umer Farooq

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Comments

Aaron Beall · Accepted Answer · 2018-04-27 17:35:55Z

Your code references 3 different arrays: this.numbers1, this.list, and this.number. It's not clear to me if that's intentional distinction, but it seems what you are trying to do is something like this:

// describe what the arrays contain
type Coord = { lat: number; lng: number; }

// define the array of those coords, initialize empty
numbers: Coord[] = [];

polygon(event){
   // push the next coord (this will be type-checked)
   this.numbers.push({ lat: event.coord.lat, lng: event.coord.lng });
}

Note that using a custom type Coord instead of any the compiler will guide you in what you are trying to do. For example this would be an error:

this.numbers.push([event.coord.lat, event.coord.lng]);

Compiles with error:

Error:
  Argument of type 'any[]' is not assignable to parameter of type 'Coord'.
    Property 'lat' is missing in type 'any[]'.

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