strong-event

a powerful event

quick start

const event = new Event()

event.on(data => console.log(data, 'index'), 1)

const subscriber = event.on(data => {
  console.log(data)
  subscriber.off()
})

event.pipe(filter(data => data > 1))
  .on(data => console.log(data, 'filter'))

event.pipe(timer(10))
  .on(data => {
    Promise.resolve('same timer is sync').then(console.log)
    console.log(data, 'timer1')
  })

event.pipe(timer(10))
  .on(data => {
    console.log(data, 'timer2')
  })

event.emit(1)
event.emit(2)

// 1
// 1 index
// 2 filter
// 2 index

/* delay 10 ms */
// 1 timer1
// 2 timer2
// same timer is sync

/* delay 20 ms */
// 1 timer1
// 2 timer2
// same timer is sync

api

Event instance

can add subscribers for a event & dispatch data by event

Event & ShareDataEvent extends BaseEvent. when you call pipe will return a ShareDataEvent instance. BaseEvent's prototype has pipe on emit error & complete methods.

`BaseEvent.prototype.on`

return a subscriber instance & you can call off to unsubscribe this event

first argument is callback or option, second argument is index of this callback (sort for subscriber's callbacks, every index saved in a array)

`BaseEvent.prototype.emit`

dispatch event for subscribers, you can emit a value

`BaseEvent.prototype.error & complete`

call it & all subscribers will not accept new event

`BaseEvent.prototype.pipe`

return a ShareDataEvent instance, & share subscribers info with event instance

argument is scheduler. like timer, filter, scan and so on. it can control subscribe(callback) how to work

you can call event or shareDataEvent emit & all of event's subscribers and all of shareDataEvent's subscribers will accept

Event

methods	arguments	description	other
`useServer`	`Server`	Server for scheduler	see scheduler
`extendEventServer`	`Event instance`	assign Servers from event	see scheduler

scheduler

builtIn schedulers

map
filter
debounceTime
timer
async
scan

you can write a scheduler, it is a simple higher-order function. but some time scheduler need a control too

// filter
function filter(fn) {
  return (data, next) => {
    fn(data) && next(data)
  }
}

// timer
function timer(time) {
  return (data, next, {timerServer}) {
    timerServer(() => next(data), time)
  }
}

so you can see same timer subscriber can call sync, becaseof Server

how to write a Server

you need use Server ?

how it work?

class BaseEvent {
  emit(data) {
    const servers = serverFactory.create() // return all Servers of event & new them
    subscribers.forEach(subscriber => exector(data, servers))
  }
}
// ServerFactory
class ServerFactory {
  create() {
    return new ServerInstance(this.servers);
  }
}
class ServerInstance {
  constructor(servers) {
    Object.keys(servers).forEach((key) => {
      this[key] = (new servers[key]()).init();
    });
  }
}

so every time you emit, will provid servers instance.

ServerClass must extends Server, if not useServer will not work.

export class TimerServer extends Server {
  constructor() {
    super();
    this.data = {};
    this.id = 1;
    this.isUpdate = false;
  }

  add(cb, time) {
    if (this.isUpdate === false) {
      this.isUpdate = true;
      Promise.resolve().then(() => {
        this.isUpdate = false;
        delete this.data[this.id];
        this.id++;
      });
    }
    if (!this.data[this.id] || !this.data[this.id][time]) {
      if (!this.data[this.id]) this.data[this.id] = {};
      this.data[this.id][time] = [cb];
      const list = this.data[this.id][time];
      setTimeout(() => list.forEach(fn => fn()), time);
    } else {
      this.data[this.id][time].push(cb);
    }
    return this.data[this.id];
  }

  init() {
    return (cb, time) => this.add(cb, time);
  }
}

name is class name but initial replaceto lowercase

about global Server

some time most of event instances need same Servers

ServerFactory.install(Server)

about defaultServers

builtIn TimerServer

new Event(false) // will not support defaultServers(TimerServer)

hz9527 / strong-event