I have a declared type
type Vehiculo={
[key: string]: string;
};
let allCars:Vehiculo = {Ford: "Ka", GM:"Sonic", Audi:"A4"};
How can I get the length of this array?
Definitely, allCars.length is not right
2 Answers
You can get the length of an array in JavaScript using
arrayVariable.length
Roughly like this:
arrayVariable = [1, 2, 3, 4, 5]
console.log(arrayVariable.length);
--
In your code you have not created an array. allCars is an object.
You could get the number of properties in your custom object using Object.keys():
var numberOfKeys = Object.keys(allCars).length;
If you need this, I have concerns about the underlying data model, though.
--
You could also use a map data structure instead of an object and then use the size property.
let allCars = new Map();
allCars.set('Ford, 'Ka);
allCars.set('GM', 'Sonic');
allCars.set('Audi', 'A4');
console.log(allCars.size);
But, I think this is going down a very different route than the code you already shared.
Comments
You need to create an array to get it's length. The syntax you have creates just an object.
class Vehiculo { // represents one vehicle
name: string;
model: string;
}
let allCars = Vehiculo[] = [
{name: 'Ford', model: 'KA'},
{name: 'Audi', model: 'A4'},
// ...so on
];
console.log(allCars.length); // will print number of cars
Object.keys(allCars).length