index.ts

        this.crop();
    }

    /**
     * Restore the emulator's viewport to the minimal size, should make all
     * the other emulator's meta-information (info, buttons, etc.) visible.
     */
    minimize() {
        const canvasContainer = document.getElementById("canvas-container")!;
        const engineCanvas = document.getElementById("engine-canvas")!;
        canvasContainer.classList.remove("fullscreen");
        engineCanvas.style.width = "";
        engineCanvas.style.height = "";
        window.removeEventListener("resize", this.crop);
    }

    crop() {
        // @todo let's make this more flexible
        const engineCanvas = document.getElementById("engine-canvas")!;

        // calculates the window ratio as this is fundamental to
        // determine the proper way to crop the fullscreen
        const windowRatio = window.innerWidth / window.innerHeight;

        // in case the window is wider (more horizontal than the base ratio)
        // this means that we must crop horizontally
        if (windowRatio > DISPLAY_RATIO) {
            engineCanvas.style.width = `${
                window.innerWidth * (DISPLAY_RATIO / windowRatio)
            }px`;
            engineCanvas.style.height = `${window.innerHeight}px`;
        } else {
            engineCanvas.style.width = `${window.innerWidth}px`;
            engineCanvas.style.height = `${
                window.innerHeight * (windowRatio / DISPLAY_RATIO)
            }px`;
        }
    }

    async fetchRom(romPath: string): Promise<[string, Uint8Array]> {
        // extracts the name of the ROM from the provided
        // path by splitting its structure
        const romPathS = romPath.split(/\//g);
        let romName = romPathS[romPathS.length - 1].split("?")[0];
        const romNameS = romName.split(/\./g);
        romName = `${romNameS[0]}.${romNameS[romNameS.length - 1]}`;

        // loads the ROM data and converts it into the
        // target byte array buffer (to be used by WASM)
        const response = await fetch(ROM_PATH);
        const blob = await response.blob();
        const arrayBuffer = await blob.arrayBuffer();
        const romData = new Uint8Array(arrayBuffer);

        // returns both the name of the ROM and the data
        // contents as a byte array
        return [romName, romData];
    }
}

type Global = {
    modalCallback: Function | null;
};

//@todo check if this is really required
const global: Global = {
    modalCallback: null
};

declare global {
    interface Window {
        panic: (message: string) => void;
    }
}

window.panic = (message: string) => {
    console.error(message);
};

const wasm = async () => {
    await _wasm();
    GameBoy.set_panic_hook_ws();
};

(async () => {
    startApp("app", BACKGROUNDS);

    const emulator = new Emulator();
    await emulator.main();
})();