Takie dela

index.ts

function combineClasses<T1, T2>(C1, C2): new (...args: any[]) => T1 & T2 {
    Object.getOwnPropertyNames(C2.prototype).forEach((name) => {
        if (name !== 'constructor') {
            C1.prototype[name] = C2.prototype[name];
        }
    });
    return Object.setPrototypeOf(C2, C1);
}

function compose<T>(...args: Array<new (...args: any[]) => T>): new (...args: any[]) => T {
    let ResultClass = args.splice(0, 1)[0];

    function applyMixins(mixins) {
        for (const Mixin of mixins) {
            ResultClass = combineClasses<T, T>(ResultClass, Mixin);
        }
    }

    applyMixins(args);

    return ResultClass;
}

describe('Compose:', () => {

    it('should apply mixins', () => {
        interface IMyBlock {
            name: string;
        }

        class MyBlock {

            public block = 'MyBlock';

            protected a: string;

            constructor(props: IMyBlock) {
                this.a = props.name;
            }

            public tag(props, state) {
                return 'a';
            }

            public attrs(props, state): any {
                return {};
            }
        }

        class MyBlockMod11 extends MyBlock {
            public tag(props, state) {
                return 'b';
            }
        }

        class MyBlockMod12 extends MyBlockMod11 {
            public tag(props, state) {
                return 'c' + super.tag(props, state);
            }

            public attrs() {
                return { id: 'the-id' };
            }
        }

        class MyBlockMod21 extends MyBlock {
            public b: string;

            constructor(props) {
                super(props);
                this.b = this.a + '1';
            }

            public attrs(props, state) {
                return { name: 'the-name', ...super.attrs(props, state) };
            }
        }

        const Test = compose(MyBlock, MyBlockMod12, MyBlockMod21);
        const res = new Test({ name: 1 }); // должно ругаться на невалидные опции конструктору

        expect(res.tag({}, {})).toBe('cb');
        expect(res.b).toBe('a1'); // НЕ должно ругаться на поле b
        expect(res.attrs({}, {})).toMatchObject({
            id: 'the-id',
            name: 'the-name',
        });
    });

});