event-context
- Event context for JavaScript
- Work in both NodeJS and browsers
- No dependencies
Features
- automatic state passing to downstream functions without explicitly declaring them in functions' parameters (think of React's context but with inheritance). State values are accessible everywhere with
ctx.getState()
- automatic disposal for every pending tasks and event listeners to prevent memory leaks. EventContext works with Promise as well, so you can abort nested unresolved promises with ease. Context disposal is accessible everywhere with
ctx.dispose()
Plugins
EventContext for jQuery (jQuery events) https://www.npmjs.com/package/event-context-plugin-jquery
EventContext for NodeJS (nextTick, EventEmitter) https://www.npmjs.com/package/event-context-plugin-node
Installation:
npm i -S event-context # to use it with a plugin, just add the plugin package npm i -S event-context-plugin-node
Usages
Passing data across functions without declaring them each time.
This is super useful to getting the request that causing an unexpected error. See the example below, it was not easy to get the req inside a downstream function without explicitly passing the req along the way.
;; // patch all NodeJS binding after this call; const server = http; { // do some works with path process;} { try ; catch ex const ctx = ; const req = ctx; const method url = req; console; }
State inheritance
State values are prototypically inherited (think of angular1's scope
).
// initiate contextsconst parent = ;const child = ; const pState = parent;const cState = child; // state can be set even before running.pStateparentOnly = 'parentOnly';pStateshared = 'parentShared'; cStatechildOnly = 'childOnly';cStateshared = 'childOverwrite'; const childComputation = ; const parentComputaion = parent;
Auto unbinding
When you decide to stop all event listeners created in an context, just call ctx.dispose()
const ctx = ;ctx
All bound event handlers within the context will be removed.
Contributions
All contributions are super welcome