Doing an operator (==) equality check in js

January 20, 2022

I have the following class:

class Coord {
    constructor(x, y) {
        this.x = x;
        this.y = y
    }
    equals(b) { // how to add this method?
        return true;
    }
}

let p1 = new Coord(1,2);
let p2 = new Coord(1,2);
console.assert(p1 == p2, 'points are not equal');

Is there a method I can add into the class such that p1 == p2 in the above? I’d like to do it within the class and not something like a JSONStringify approach.

The equivalent in python I would do would be:

class Coord:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def __eq__(self, o):
        return (self.x == o.x) and (self.y == o.y)

p1 = Coord(1,2);
p2 = Coord(1,2);
print (p1==p2)
# True

>Solution :

An alternative

class Coord {
    constructor(x, y) {
        this.x = x;
        this.y = y
    }

    valueOf(b) { 
        return `${x},${y}`
    }
}

let p1 = new Coord(1,2);
let p2 = new Coord(1,2);
console.assert(p1.valueOf() == p2.valueOf(), 'points are not equal');