Pure Saga

Pure saga is a functional implementation of generator based asynchronous flow manager based on effects yielding. It has been inspired with redux-saga.

Installation

Via npm:

npm i pure-saga

Or via unpkg.com:

<script src="https://unpkg.com/pure-saga@3/dist/pure-saga.js"></script>
<script src="https://unpkg.com/pure-saga@3/dist/pure-saga.min.js"></script>

Usage

Pure-saga allows developer to define custom effects to implement any behavior. It has pretty simple interface createSaga(generatorFunc, sagaEffects). This function returns promisified saga generator. See example below of how to use it.

Example

This example shows how to create API for saga like this:

import {createSaga} from 'pure-saga';

// Side effects handlers get instructions generated by factories and produce
// result. Side effect could return promises.
const effectHandlers = {
    api: ({method, args}) => api[method](...args),
    storagePut: ({id, item}) => storage.set(id, item),
    storageGet: ({id, item}) => storage.get(id),
};

// Define some goodies for easy effect creation.
const createEffect = (type, payload) => ({type, payload});

// Effects factory
const effects = {
    api: (method, ...args) => createEffect('api', {method, args}),
    storage: {
        put: (id, item) => createEffect('storagePut', {id, item}),
        get: (id) => createEffect('storageGet', {id}),
    },
};

// Example saga generator function
function * loadUserSaga(userId) {
    // Retrieve user calling api.loadUser method
    const user = yield effects.api('loadUser', userId);
    // Put user to storage
    yield effects.storage.put(user.id, user);
}

// Create method
const loadUser = createSaga(loadUserSaga, effectHandlers);

// Use it
loadUser(1)
.catch((error) => console.error(error));

Testing

Test example.

function * getUserSaga() {
    const user = yield effect.get('user');

    return user;
}

describe('getUserSaga', () => {
    it('Should yield `get` effect', () => {
        const it = getUserSaga();

        const effect = it.next().value;

        // Check effect to be an instanceof get effect.
        should(effect).be.deepEqual({
            type: 'get',
            payload: {
                key: 'user',
            },
        });

        const user = {name: 'user'};
        const result = it.next(user).value;

        should(result).be.deepEqual(user);
    });
});

License

MIT.