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Typescript – Class Instance Variable As An Accessor To The First Value In A Set

August 15, 2022

In a typescript class, are you able to specify an instance variable as a shortcut to access the first value in a Set?

What I want to do is something like this:

export class Car {
    public gears: Set<string>;
    public gear: string => gears?.values().next().value; // doesn't work

    constructor() {
        gears = new Set<string>(["N", "First", "Second", "Third", "Fourth"]);
    }
}

Usage:

var car = new Car();
console.log(car.gear); // => "N"

I know you can do it with a function like

public gear = (): string => gears?.values().next().value;

But when you call that you need to call it as a function instead of an instance variable

var car = new Car();
console.log(car.gear()); // => "N"

While that works, it’s not ideal because semantically it doesn’t make a lot of sense that gear is a function.

Is what I’m asking possible in Typescript?

>Solution :

You’re looking for a getter :

export class Car {
    public gears: Set<string>;
    public get gear(): string {
        return this.gears.values().next().value
    }

    constructor() {
        this.gears = new Set<string>(["N", "First", "Second", "Third", "Fourth"]);
    }
}

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