Why EVT ?

'evt' is intended to be a replacement for 'events'. It enables and encourages functional programming and makes heavy use of typescript's type inference features to provide type safety while keeping things concise and elegant 🍸.

Suitable for any JS runtime env (deno, node, old browser, react-native ...)

  • ✅ It is both a Deno and an NPM module.

  • ✅ Lightweight, no dependency.

  • ✅ No polyfills needed, the NPM module is transpiled down to ES3.

Can be imported in TypeScript projects using version >= 3.4 (Mar 2019) and in any plain JS projects.

Motivation

There are a lot of things that can't easily be done with EventEmitter:

  • Enforcing type safety.

  • Removing a particular listener ( if the callback is an anonymous function ).

  • Adding a one-time listener for the next event that meets a condition.

  • Waiting (via a Promise) for one thing or another to happen.

    Example: waiting at most one second for the next message, stop waiting if the socket disconnects.

Why would someone pick EVT over RxJS:

  • RxJS introduces a lot of abstractions. It's a big jump from EventEmitter.

  • It is often needed to resort to custom type guards, the filter operator breaks the type inference.

  • Tend to be quite verbose.

  • It could be months before it eventually supports Deno.

  • There is no official guideline on how to integrate it with React.

EVT is an attempt to address all these points while trying to remain as accessible as EventEmitter.