updux/src/subscriptions.test.js

import tap from 'tap';
import u from '@yanick/updeep';

import { Updux } from './Updux.js';
import { action } from './actions.js';

tap.test('subscriptions', async () => {
    const inc = action('inc');
    const set_copy = action('set_copy');

    const dux = new Updux({
        initial: {
            x: 0,
            copy: 0,
        },
        actions: {
            inc,
            set_copy,
        },
        mutations: {
            inc: (payload) => u({ x: (x) => x + 1 }),
            set_copy: (copy) => u({ copy }),
        },
    });

    dux.addSubscription((store) => (state, previous, unsubscribe) => {
        if (state.x > 2) return unsubscribe();

        store.dispatch(set_copy(state.x));
    });

    const store = dux.createStore();

    store.dispatch(inc());

    tap.same(store.getState(), { x: 1, copy: 1 });

    store.dispatch(inc());
    store.dispatch(inc());

    tap.same(store.getState(), { x: 3, copy: 2 }, 'we unsubscribed');
});

tap.test('subduxes subscriptions', async (t) => {
    const inc_top = action('inc_top');
    const inc_bar = action('inc_bar');
    const transform_bar = action('transform_bar');

    const bar = new Updux({
        initial: 'a',
        actions: { inc_bar, transform_bar },
        mutations: {
            inc_bar: () => (state) => state + 'a',
            transform_bar: (outcome) => () => outcome,
        },
        subscriptions: [
            (store) => (state, previous, unsubscribe) => {
                if (state.length <= 2) return;
                unsubscribe();
                store.dispatch(transform_bar('look at ' + state));
            },
        ],
    });

    const dux = new Updux({
        initial: {
            count: 0,
        },
        subduxes: { bar },
        actions: {
            inc_top,
        },
        mutations: {
            inc_top: () => u({ count: (count) => count + 1 }),
        },
        effects: {
            '*': () => (next) => (action) => {
                next(action);
            },
        },
        subscriptions: [
            (store) => {
                return ({ count }, { count: previous } = {}) => {
                    if (count !== previous) {
                        previous = count;
                        store.dispatch.inc_bar();
                    }
                };
            },
        ],
    });

    const store = dux.createStore();

    store.dispatch(inc_top());
    store.dispatch(inc_top());

    t.same(store.getState(), {
        count: 2,
        bar: 'look at look at aaa',
    });
    store.dispatch(inc_top());
    t.same(store.getState(), {
        count: 3,
        bar: 'look at look at aaaa',
    });
});