Many times we are in situations we want to compare instances of a class, aka objects, for example in case you develop a game and you want to compare instances of a gameobject, e.g. Car
:
class Car {
constructor(speed){
this.speed = speed
}
}
Let's say we want to compare instances of a car (or sort/filter an array of them). Obviously we can do:
const car1 = new Car(100)
const car2 = new Car(120)
const car3 = new Car(90)
console.log(car2.speed > car1.speed) // true
const sorted = [car1, car2, car3].sort((a,b) => {
return a.speed - b.speed;
});
This works perfectly fine but we can do better, so we donβt have to type .speed
every time we want to compare two cars, or sort/filter an array of them. We can define a valueOf method in the Car class, the method returns the βvalueβ of the instance.
class Car {
constructor(speed){
this.speed = speed
}
valueOf(){
return this.speed;
}
}
const car1 = new Car(100)
const car2 = new Car(120)
const car3 = new Car(90)
console.log(car2 > car1) // true
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