util/tui-app.js


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// General-purpose wrapper code that can be used as the base of a tui-lib
// program. Contained to reduce boilerplate and improve consistency between
// programs.

const ansi = require('./ansi');

const CommandLineInterfacer = require('./CommandLineInterfacer');
const Flushable = require('./Flushable');
const Root = require('../ui/Root');

module.exports = async function tuiApp(callback) {
    // TODO: Support other interfacers.
    const interfacer = new CommandLineInterfacer();

    const flushable = new Flushable(process.stdout, true);

    const root = new Root(interfacer);

    const size = await interfacer.getScreenSize();
    root.w = size.width;
    root.h = size.height;
    flushable.resizeScreen(size);

    interfacer.on('resize', newSize => {
        root.w = newSize.width;
        root.h = newSize.height;
        flushable.resizeScreen(newSize);
        root.fixAllLayout();
    });

    const cleanTerminal = function () {
        process.stdout.write(ansi.cleanCursor());
        process.stdout.write(ansi.disableAlternateScreen());
    };

    const dirtyTerminal = function () {
        process.stdout.write(ansi.enableAlternateScreen());
        process.stdout.write(ansi.startTrackingMouse());
    };

    const quitProgram = function (status = 0) {
        cleanTerminal();
        process.exit(status);
    };

    const suspendProgram = function () {
        cleanTerminal();
        process.kill(process.pid, 'SIGTSTP');
    };

    const startRenderLoop = function () {
        dirtyTerminal();

        process.on('SIGCONT', () => {
            flushable.clearLastFrame();
            process.stdin.setRawMode(false);
            process.stdin.setRawMode(true);
            dirtyTerminal();
        });

        setInterval(() => {
            root.renderTo(flushable);
            flushable.flush();
        });
    };

    try {
        return await callback({
            root,
            startRenderLoop,
            suspendProgram,
            quitProgram
        });
    } catch (error) {
        cleanTerminal();
        console.error(error);
        process.exit(1);
    };
};