@jawis/jab NPM

@jawis/jab

JavaScript basic is a collection of utilities. Can be used in both node and web projects.

Installation

yarn add @jawis/jab

npm i @jawis/jab

Usage

Documentation: Everything is developed in TypeScript, so type declarations are the best place to find information about the individual functions and classes.

Here are some highlights:

Waiter

Waiter is meant to be used by an object, that wishes to keep control over asynchronous state. It's most instructive to show how LoopController gives access to its underlying Waiter.

//create a loop controller, that runs five iterations.
//It starts execution automatically.

const lc = new LoopController({
  arr: [1, 2, 3, 4, 5],
  makePromise: (index) => {
    console.log("iteration: " + index);
    return sleeping(10);
  },
  onError: console.log,
});

//await first iteration finishes, and pause it.

lc.waiter.await("iteration-done").then(() => {
  //LoopController will receice a pause command
  // in a certain state.
  lc.pause();
});

This way we can 'inject' actions when LoopController makes state transitions or emit events. It's a powerful way to do white-box testing.

The example is a little flaky though. There's no guarantee when the pause will execute. So Waiter should also support callback style. The promise style is less intrusive though. Injecting actions synchronous when LoopController changes state or emits events could break its assumptions. One would have to ensure it has finished its execution for the current tick, when it set state or emits event.

FinallyProvider

Provides the ability to register functions, that should be executed before shutdown.

const finalProv = new FinallyProvider({
  onError: console.log,
});

//Execute where needed

finalProv.finally(() => {
  console.log("Clean up stuff here.");
});

//Execute just before shutdown

finalProv.runFinally().then(() => {
  console.log("Ready to exit.");
});

Small utilities

getProtoChain: Returns the prototype chain of an object as an array of 'class' names.

Build

All imports are side effect free. So this library is ideal for tree-shaking.

Known issues

indent has a bug.
clone
- Handles binary data superficially.
- Sparsity in arrays is not preserved.
- Non-enumerable properties is not preserved.
ES6 is required minimum. Because JabError inherits from Error