Jellyfish.js NPM

Jellyfish

Multiplayer game development made easy.

Jellyfish is a game engine designed around multiplayer. We handle networking, sending packets, and updating state, so you can focus on what you care about — designing your game.

Features

Write your code once, run the same bundle on the server and the client, and we take care of the rest. State is automatically synchronized between clients.
Supports WebGL rendering (thanks to PIXI.js) and optionally, physics (thanks to matter.js).
Supports JavaScript and TypeScript.
No IDE. You already like your editor, and we could never compete with it. Use what you're comfortable with.
Easy to learn, but powerful. Jellyfish isn't magic — it does things automatically when you want, but let's you control the details when you need.

Simple Multiplayer Game

const { GameObject, ImageSprite, Vector, Server, Client, isServer, game, serve } = require('jellyfish.js');

class Player extends GameObject {
    onCreate() {
        this.position = Vector.xy(100, 300);
        this.sprite = this.createSprite(ImageSprite, '/assets/player.png');
        this.sprite.following = this;
    }

    keyHeld(keycode) {
        if (!this.isOwnedByCurrentUser()) { return; }

        let movement = Vector.zero;
        switch (keycode) {
            case 40: movement = Vector.up; break;
            case 38: movement = Vector.down; break;
            case 37: movement = Vector.left; break;
            case 39: movement = Vector.right; break;
        }

        this.position = this.position.plus(movement);
    }
}
game.registerClass(Player);

class GameServer extends Server {
    onCreate() { this.start(); }
}

class GameClient extends Client {
    onCreate() { this.connect(); }
    onRegistered() {
        const player = this.createObject(Player);
        player.setOwner(this.user());
    }
}

if (isServer) { game.createObject(GameServer); }
else { game.createObject(GameClient); }

game.setCanvasByID("game");
game.start();
serve();