index.mjs

// type "node index.mjs" for run
import assert from 'assert';
import test, { describe } from 'node:test';

export default function classes(BasesArg) {
    class Bases {
        constructor() {
            BasesArg.forEach((Base) => Object.assign(this, new Base()));
        }
    }
    function addPrototype(Class) {
        if (!Class?.prototype) {
            return;
        }
        const names = Object.getOwnPropertyNames(Class.prototype);
        names
            .filter((prop) => prop !== 'constructor')
            .forEach((prop) => (Bases.prototype[prop] = Class.prototype[prop]));
        addPrototype(Object.getPrototypeOf(Class));
    }
    BasesArg.forEach((Base) => {
        addPrototype(Base);
    });
    return Bases;
}

describe('classes tests', async () => {
    test('classes 1', (t) => {
        class A {
            a() {
                return 'a';
            }
        }
        class B extends A {
            b() {
                return 'b';
            }
        }
        class C extends B {
            c() {
                return 'c';
            }
        }
        class D {
            d() {
                return 'd';
            }
        }
        class E extends classes([C, D]) {
            constructor() {
                super();
            }
            e() {
                return 'e';
            }
        }
        const eObj = new E();
        assert.strictEqual(eObj.e(), 'e');
        assert.strictEqual(eObj.d(), 'd');
        assert.strictEqual(eObj.c(), 'c');
        assert.strictEqual(eObj.b(), 'b');
        assert.strictEqual(eObj.a(), 'a');
    });

    test('classes 2', (t) => {
        class A {
            a() {
                return 'a';
            }
        }
        class B extends A {}
        class C extends B {
            c() {
                return 'c';
            }
        }
        class D {
            d() {
                return 'd';
            }
        }
        class E extends classes([C, D]) {
            constructor() {
                super();
            }
            e() {
                return 'e';
            }
        }
        const eObj = new E();
        assert.strictEqual(eObj.e(), 'e');
        assert.strictEqual(eObj.d(), 'd');
        assert.strictEqual(eObj.c(), 'c');
        assert.strictEqual(eObj.a(), 'a');
    });
});