@esfx/equatable

The @esfx/equatable package provides a low level API for defining equality.

Overview

• Installation
• Usage
• API

Installation

npm i @esfx/equatable

Usage

import { Equatable, Equaler, Comparable, Comparer } from "@esfx/equatable"; 

class Person {
    constructor(firstName, lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    toString() {
        return `${this.firstName} ${this.lastName}`;
    }

    [Equatable.equals](other) {
        return other instanceof Person
            && this.lastName === other.lastName
            && this.firstName === other.firstName;
    }

    [Equatable.hash]() {
        return Equaler.defaultEqualer.hash(this.lastName)
             ^ Equaler.defaultEqualer.hash(this.firstName);
    }

    [Comparable.compareTo](other) {
        if (!(other instanceof Person)) throw new TypeError();
        return Comparer.defaultComparer.compare(this.lastName, other.lastName)
            || Comparer.defaultComparer.compare(this.firstName, other.firstName);
    }
}

const people = [
    new Person("Alice", "Johnson")
    new Person("Bob", "Clark"),
];
people.sort(Comparer.defaultComparer.compare);
console.log(people); // Bob Clark,Alice Johnson

const obj1 = new Person("Bob", "Clark");
const obj2 = new Person("Bob", "Clark");
obj1 === obj2; // false
Equaler.defaultEqualer.equals(obj1, obj2); // true

API

You can read more about the API here.