A browser-based event emitter, for tying things together.
npm install knot.js
A browser-based event emitter, for tying things together.
Knot was developed with a modern JavaScript workflow in mind. To use it, it's recommended you have a build system in place that can transpile ES6, and bundle modules. For a minimal boilerplate that does so, check out outset.
Follow these steps to get started:
Then dig into the API.
Using NPM, install Knot.js, and add it to your package.json dependencies.
``
$ npm install knot.js --save
Simply import Knot, then call it.
* Passed _no parameters_, Knot will return a new emitter
* Passed _an object_, Knot will extend it to include the emitter methods
Note that the this context in the event handlers:
* Is the object passed in, if one was provided
* Otherwise, it is the emitter itself
`es6
// import Knot
import knot from 'knot.js'
// create a new emitter
// in the handlers, 'this' refers to the emitter
const emitter = knot()
// extend an existing object, transforming it into an emitter
// in the handlers, 'this' refers to the Class
const object = new Class()
const extended = knot(object)
`
All methods are chainable.
Knot exposes the following API:
Add a handler to a new or existing event.
`es6
// add an anonymous function as a handler
emitter.on('name', () => {
// ...
})
// add a named function as a handler
const handler = () => {
// ...
}
emitter.on('name', handler)
`
Add a handler, that fires _only once_, to a new or existing event.
`es6
// add an anonymous function as a handler
emitter.once('name', () => {
// ...
})
// add a named function as a handler
const handler = () => {
// ...
}
emitter.once('name', handler)
`
Remove a specific handler from an event.
`es6
// handler must be a named function
const handler = () => {
// ...
}
emitter.off('name', handler)
`
Remove all of an event's handlers.
`es6`
emitter.off('name')
Emit an event, firing all of its handlers.
`es6`
emitter.emit('name')
Optionally, include arguments that will be passed to each handler.
`es6
// accept arguments in handler
emitter.on('name', (a, b, c, d) => console.log(a, b, c, d))
// include arguments in call to emit
emitter.emit('name', 1, '2', [3], {})
// LOG: 1 '2' [3] {}
``
Tested in all modern browsers and IE10+.
MIT. © 2016 Michael Cavalea
