EventsReceiver

Attribute name	Type	Description
eventNames	string | string[]	Event name or array of event names
receiver	(eventName: string, eventData: any, stateManager: StateManager):void | Promise<any>	This function will be called when one of required events will be called.

EventsReceiver can handle one or more events. Thats mean when You emit some event. Eventrix will invoked receiver when event name match to his events list.

Javascript

import { EventsReceiver } from 'eventrix';

const removeUserReceiver = new EventsReceiver(
    'Users:remove.user',
    (eventName, eventData, stateManager) => {
        const usersList = stateManager.getState('users');
        const newUsersList = usersList.filter(user => user.id !== eventData.id);
        stateManager.setState('users', newUsersList);
    }
);

export default removeUserReceiver;

Typescript

import { EventsReceiver } from 'eventrix';
import StateManager from 'eventrix/types/StateManager';
import { User } from '../interfaces';

interface RemoveUserEventData {
    id: number;
}

const removeUserReceiver = new EventsReceiver<RemoveUserEventData, void>(
    'Users:remove.user',
    (eventName, eventData, stateManager) => {
        const usersList = stateManager.getState<User[]>('users');
        const newUsersList = usersList.filter(user => user.id !== eventData.id);
        stateManager.setState<User[]>('users', newUsersList);
    }
);

export default removeUserReceiver;

You can also listen on list of events and check which event was emitted.

Javascript

import { EventsReceiver } from 'eventrix';

const usersReceiver = new EventsReceiver(
    ['Users:add.user', 'Users:remove.user'],
    (eventName, eventData, stateManager) => {
        const usersList = stateManager.getState('users');
        if (eventName === 'Users:add.user') {
            stateManager.setState('users', [...usersList, eventData]);
        }
        if (eventName === 'Users:remove.user') {
            const newUsersList = usersList.filter(user => user.id !== eventData.id);
            stateManager.setState('users', newUsersList);
        }
    }
);

export default usersReceiver;

Typescript

import { EventsReceiver } from 'eventrix';
import StateManager from 'eventrix/types/StateManager';
import { User } from '../interfaces';

interface RemoveUserEventData {
    id: number;
}

const removeUserReceiver = new EventsReceiver<RemoveUserEventData | User, void>(
    ['Users:add.user', 'Users:remove.user'],
    (eventName, eventData, stateManager): void => {
        const usersList = stateManager.getState<User[]>('users');
        if (eventName === 'Users:add.user') {
            stateManager.setState<User[]>('users', [...usersList, eventData]);
        }
        if (eventName === 'Users:remove.user') {
            const newUsersList = usersList.filter(user => user.id !== eventData.id);
            stateManager.setState<User[]>('users', newUsersList);
        }
    }
);

export default removeUserReceiver;

When You need handle some async action You can return Promise. If receiver return Promise then Eventrix wait for Promise resolve and You can handle state change when Promise resolved.

Javascript

import { EventsReceiver } from 'eventrix';
import axios from 'axios';

const createUserReceiver = new EventsReceiver(
    'Users:create.user',
    (eventName, eventData, stateManager) => {
        return axios.post(`http://users.com/users`, eventData)
             .then((response) => {
                 const newUser = response.data;
                 const usersList = stateManager.getState('users');
                 stateManager.setState('users', [...usersList, newUser]);
             });
    }
);

export default createUserReceiver;

Typescript

import { EventsReceiver } from 'eventrix';
import StateManager from 'eventrix/types/StateManager';
import { User } from '../interfaces';
import axios from 'axios';

const createUserReceiver = new EventsReceiver<User, Promise<User>>(
    'Users:create.user',
    (eventName, eventData, stateManager) => {
        return axios.post(`http://users.com/users`, eventData)
             .then((response: { data: User }): User => {
                 const newUser = response.data;
                 const usersList = stateManager.getState('users');
                 stateManager.setState('users', [...usersList, newUser]);
                 return newUser;
             });
    }
);

export default createUserReceiver;

Complete example how use EventsReceiver

Javascript

import { EventsReceiver, Eventrix } from 'eventrix';

const initialState = {
    users: [],
};

const removeUserReceiver = new EventsReceiver(
    'Users:remove.user',
    (eventName, eventData, stateManager) => {
        const usersList = stateManager.getState('users');
        const newUsersList = usersList.filter(user => user.id !== eventData.id);
        stateManager.setState('users', newUsersList);
    }
);

const receivers = [removeUserReceiver];

const eventrix = new Eventrix(initialState, receivers);

export default eventrix;

Typescript

import { EventsReceiver, Eventrix } from 'eventrix';
import StateManager from 'eventrix/types/StateManager';

interface User {
    id: number;
    name: string;
    age: number;
}

interface StoreState {
    usersList: User[];
}

const initialState = {
    users: [],
};

const removeUserReceiver = new EventsReceiver<User, void>(
    'Users:remove.user',
    (eventName, eventData, stateManager): void => {
        const usersList = stateManager.getState<User[]>('users');
        const newUsersList = usersList.filter(user => user.id !== eventData.id);
        stateManager.setState<User[]>('users', newUsersList);
    }
);

const receivers = [removeUserReceiver];

const eventrix = new Eventrix<StoreState>(initialState, receivers);

export default eventrix;

You can register EventsReceiver later by:

eventrix.useReceiver(createUserReceiver);

or remove receiver by:

eventrix.removeReceiver(createUserReceiver);