What is d3-dispatch?
The d3-dispatch module provides a simple mechanism for registering named callbacks and dispatching events to those callbacks. It is part of the D3.js library and is useful for managing events in a modular and decoupled way.
What are d3-dispatch's main functionalities?
Creating a Dispatcher
This feature allows you to create a dispatcher with named events. In this example, a dispatcher is created with two events: 'start' and 'end'.
const d3 = require('d3-dispatch');
const dispatch = d3.dispatch('start', 'end');
Registering Callbacks
This feature allows you to register callbacks for the named events. Here, two callbacks are registered: one for the 'start' event and one for the 'end' event.
dispatch.on('start', () => console.log('Started!'));
dispatch.on('end', () => console.log('Ended!'));
Dispatching Events
This feature allows you to dispatch events, triggering the registered callbacks. In this example, the 'start' and 'end' events are dispatched, causing the respective callbacks to be executed.
dispatch.call('start');
dispatch.call('end');
Passing Arguments to Callbacks
This feature allows you to pass arguments to the callbacks when dispatching events. Here, a message is passed to the 'start' event callback.
dispatch.on('start', (message) => console.log('Started:', message));
dispatch.call('start', null, 'Initialization complete');
Other packages similar to d3-dispatch
eventemitter3
EventEmitter3 is a high performance EventEmitter for Node.js and the browser. It provides a similar event dispatching mechanism but is more general-purpose and not tied to the D3.js ecosystem.
mitt
Mitt is a tiny functional event emitter. It is very lightweight and provides a simple API for event handling, making it a good alternative for small projects or when minimal overhead is desired.
node-event-emitter
Node-Event-Emitter is a simple and lightweight event emitter for Node.js. It offers similar functionality to d3-dispatch but is designed specifically for Node.js environments.
d3-dispatch
Register named callbacks and call them with arguments. This code is currently EXPERIMENTAL and represents the in-development D3 4.0 API. The 4.0 API is largely backwards-compatible, but differs from 3.x in several ways:
- It is now an error to attempt to register an event type that: conflicts with a JavaScript built-in object property, such as
__proto__
or hasOwnProperty
; conflicts with a built-in method on dispatch (namely, on
); or is a duplicate.