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💧EventEmitter's typesafe replacement
garronej/evt
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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.

Concerning RxJS:

  • It 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.

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