nanobus [![stability][0]][1]

[![npm version][2]][3] [![build status][4]][5] [![test coverage][6]][7]
[![downloads][8]][9] [![js-standard-style][10]][11]

Tiny message bus.

Usage

``js
var nanobus = require('nanobus')
var bus = nanobus()

bus.on('foo', function (color) {
console.log('color is', color)
})

bus.emit('foo', 'blue')
`

FAQ

$3

We had the requirement for a * event to catch all calls, and figured we could
improve the file size at the same time. This library is about 1/3rd the size of
Node's version. And it was easy to build, so yeah good enough of an excuse hah.

$3

You can do this by using the .once() listener and establishing a convention
around naming schemas.

`js
bus.on('foo', function (color) {
console.log('foo called')
bus.emit('foo:res')
})

bus.once('foo:res', function () {
console.log('response received')
})
bus.emit('foo')
`

$3


If you're only writing code that runs inside Node and don't need a '*'
listener, consider using the built-in event emitter API instead.

$3

No. If you're interested in doing that, use something like
nanotick to batch events and ensure
they run asynchronously.

API

$3

Create a new nanobus instance. Optionally takes a name that will be used for
tracing in the browser using the performance.mark / performance.measure
API.

$3

Emit an event. Arbitrary data can optionally be passed as an argument. '*'
listeners run after named listeners.

$3

$3

Listen to an event. If the event name is '*' the listener signature is
listener(eventName, [data], [performanceTimingId]).

$3

Listen to an event, but make sure it's pushed to the start of the listener
queue. If the event name is '*' the listener signature is
listener(eventName, [data]).

$3

Listen to an event, and clear it after it's been called once. If the event
name is '*' the listener signature is
listener(eventName, [data], [performanceTimingId]).

$3

Listen to an event, and clear it after it's been called once. If the event
name is '*' the listener signature is listener(eventName, [data]).

$3

Remove a specific listener to an event.

$3

Return all listeners for a given event. '*' listeners are not included in
this list. Use bus.listeners('') to get a list of '' listeners.

$3

Remove all listeners to an event. If no event name is passed, removes all
listeners on the message bus. '*' listeners are not removed unless
eventName is * or no event name is passed.

TypeScript

Optional event typing is available in TypeScript by passing an object type with
event names as keys and event listener function signatures as values.

`ts
// if compilerOptions.esModuleInterop = true
import Nanobus from "nanobus"
// else
import Nanobus = require("nanobus")

type Events = {
foo: (color: string) => void
bar: (count: number) => void
}

const bus = new Nanobus()

bus.on("foo", color => {
// color: string
console.log("color is", color)
})

bus.on("bar", count => {
// count: number
console.log("count is", count)
})

bus.on("*", (eventName, data) => {
// eventName: "foo" | "bar"
// data: any[]
if (eventName === "foo") {
const [color] = data as Parameters
// color: string
} else if (eventName === "bar") {
const [count] = data as Parameters
// count: number
}
})

bus.emit("foo", "blue") // required arguments: [string]
bus.emit("bar", 100) // required arguments: [number]
``

License

MIT

[0]: https://img.shields.io/badge/stability-experimental-orange.svg?style=flat-square
[1]: https://nodejs.org/api/documentation.html#documentation_stability_index
[2]: https://img.shields.io/npm/v/nanobus.svg?style=flat-square
[3]: https://npmjs.org/package/nanobus
[4]: https://img.shields.io/travis/choojs/nanobus/master.svg?style=flat-square
[5]: https://travis-ci.org/choojs/nanobus
[6]: https://img.shields.io/codecov/c/github/choojs/nanobus/master.svg?style=flat-square
[7]: https://codecov.io/github/choojs/nanobus
[8]: http://img.shields.io/npm/dm/nanobus.svg?style=flat-square
[9]: https://npmjs.org/package/nanobus
[10]: https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat-square
[11]: https://github.com/feross/standard