@yamiteru/cynic

Cynic

Tiny and simple TS pub/sub library with great focus on performance.
(run yarn benchmark too see how much faster Cynic is)

Installation

yarn add @yamiteru/cynic

Concept

Most pub/sub libraries are based on string matching. Some even add an additional wildcard matching like player.*. Although this is a valid approach it's usually unnecessary.

We can simply externalize the internal nested structure of player.* into our custom data structure (object, array, etc.) and logic around it.

This makes the inner workings of the library more transparent and also more performant since we don't have to match an unknown string to a dynamic structure. Also we get type safety as a bonus!

The player.* structure can be expressed as a simple object just like this:

const player = {
    position: event{ x: number, y: number, z: number }(),
    health: event<number>(),
    money: event<number>(),
};

And can be cleared just like this:

for (const event$ of player) {
    clear(event$);
}

Cynic internally uses sets as opposed to objects, maps or arrays. Since sets have time complexity of O(1) for .add, .delete and .has they're a great candidate for storing and accessing data.

Also when you subscribe to a event you get back an unsubscribe function so you don't have to store callbacks in constants in order for you to unsubscribe a callback.

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Usage

// Event w/ input
const playerPosition$ = event<{ x: number, y: number, z: number }>();

// Event w/o input
const clicked$ = event<undefined>();

// Event that triggers only once
const once$ = once<number>();

subscribe

const playerPositionUnsubscribe = subscribe(playerPosition$, (pos) => {
    notifyEnemies(pos);
    updateChunks(pos);
});

publish

// event
publish(playerPosition$, {
    x: 10, y: 0, z: 4
});

size

const subCount = size(playerPosition$);

has

const hasLog = has(playerPosition$, console.log);

clear

clear(playerPosition$);

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Modularity

Each event is basically just a wrapper around a set. This set is stored in an object property using a secret symbol. Thanks to this it can be accessed by official functions provided by this package but cannot be accessed anywhere else.

Thanks to this Cynic is very tree-shakable. If you think there should be more official functions just create a PR! I'm very open to any improvement of this library.

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Have a beautiful day 🍀