Package Exports

first-event

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (first-event) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

first-event

Race event-emitter events, resolves the first to occur. Promise-based ee-first

Installation

npm install --save first-event

Usage

Error Example

var first = require('first-event')
var ee = new EventEmitter()

first(ee, ['error', 'foo', 'bar'])
  .catch(function (err) {
    // error from emit 'error' gets sent here
    console.log(err) // [ Error: 'boom' ]
  })

ee.emit('error', new Error('boom'))
// below does nothing, bc it happenned second
ee.emit('foo', 1)

Event Example

var first = require('first-event')
var ee = new EventEmitter()

first(ee, ['error', 'foo', 'bar'])
  .then(function (firstEvent) {
    console.log(firstEvent.ee)    // [ EventEmitter: ... ]
    console.log(firstEvent.event) // 'foo'
    console.log(firstEvent.args)  // [ 'one', 'two', 'three' ]
  })

ee.emit('foo', 'one', 'two', 'three')
// below does nothing, bc it happenned second
ee.emit('bar', 1)

Race Events from different EventEmitters

var first = require('first-event')
var ee = new EventEmitter()
var ee2 = new EventEmitter()

Promise.race(
  first(ee, ['error', 'foo', 'bar'])
  first(ee2, ['error', 'foo', 'bar'])
).then(function (firstEvent) {
  console.log(firstEvent.ee)    // [ EventEmitter: ... ] === ee2
  console.log(firstEvent.event) // 'foo'
  console.log(firstEvent.args)  // [ 'one', 'two', 'three' ]
})

ee2.emit('foo', 'one', 'two', 'three')
// below does nothing, bc it happenned second
ee.emit('bar', 1)

Cancel

var first = require('first-event')
var ee = new EventEmitter()
var eventPromise = first(ee, ['error', 'foo', 'bar'])

eventPromise
  .then(function (data) {
    // never happens, bc event handlers were cancelled below
  }).catch(function () {
    // never happens, bc event handlers were cancelled below
  })

// cancel and cleanup event handlers
eventPromise.cancel()
// below will do nothing, bc the event handlers were removed
ee.emit('foo', 1)

License

MIT