@stoplight/lifecycle

Event and disposable helpers.

• Explore the interfaces: TSDoc
• View the changelog: Releases

Features

• Disposable helpers.
• Event emitter helpers.

Installation

Supported in modern browsers and node.

# latest stable
yarn add @stoplight/lifecycle

Usage

Disposables

A standardized way for things to declare how they cleanup. Simple example below:

import {
  DisposableCollection,
  EventEmitter,
  IDisposable
} from "@stoplight/lifecycle";

export class Editor implements IDisposable {
  // EventEmitter itself is an IDisposable
  public readonly valueEmitter = new EventEmitter<string, "didUpdate">();

  private readonly disposables: DisposableCollection = new DisposableCollection();

  constructor() {
    this.disposables.push(this.valueEmitter);
  }

  // Implement IDisposable
  dispose() {
    this.disposables.dispose();
  }
}

Emitter

A simple example editor that allows users to subscribe to value update events.

import { EventEmitter, IDisposable } from "@stoplight/lifecycle";

class Editor implements IDisposable {
  private _value = "";

  // create an emitter instance for this editor, defining the possible events and event object value
  private valueEmitter = new EventEmitter<string, "willUpdate" | "didUpdate">();

  get value() {
    return this._value;
  }

  set value(val: string) {
    this.valueEmitter.emit("willUpdate", this._value);
    this._value = val;
    this.valueEmitter.emit("didUpdate", this._value);
  }

  get onWillUpdateValue() {
    return this.valueEmitter.on("willUpdate");
  }

  get onDidUpdateValue() {
    return this.valueEmitter.on("didUpdate");
  }

  dispose() {
    // best practice to cleanup the emitter
    this.valueEmitter.dispose();
  }
}

const editor = new Editor();

const willUpdateListener = editor.onWillUpdateValue(val => {
  console.log("next value: ", val);
});

const didUpdateListener = editor.onDidUpdateValue(val => {
  console.log("new value: ", val);
});

// stop listening to willUpdate event
willUpdateListener.dispose();

Contributing

1. Clone repo.
2. Create / checkout feature/{name}, chore/{name}, or fix/{name} branch.
3. Install deps: yarn.
4. Make your changes.
5. Run tests: yarn test.prod.
6. Stage relevant files to git.
7. Commit: yarn commit. NOTE: Commits that don't follow the conventional format will be rejected. yarn commit creates this format for you, or you can put it together manually and then do a regular git commit.
8. Push: git push.
9. Open PR targeting the next branch.