node_modules/cli-progress/lib/single-bar.js

const _GenericBar = require('./generic-bar');
const _options = require('./options');

// Progress-Bar constructor
module.exports = class SingleBar extends _GenericBar{

    constructor(options, preset){
        super(_options.parse(options, preset));

        // the update timer
        this.timer = null;

        // disable synchronous updates in notty mode
        if (this.options.noTTYOutput && this.terminal.isTTY() === false){
            this.options.synchronousUpdate = false;
        }

        // update interval
        this.schedulingRate = (this.terminal.isTTY() ? this.options.throttleTime : this.options.notTTYSchedule);

        // callback used for gracefulExit
        this.sigintCallback = null;
    }

    // internal render function
    render(){
        // stop timer
        if (this.timer){
            clearTimeout(this.timer);
            this.timer = null;
        }

        // run internal rendering
        super.render();

        // add new line in notty mode!
        if (this.options.noTTYOutput && this.terminal.isTTY() === false){
            this.terminal.newline();
        }

        // next update
        this.timer = setTimeout(this.render.bind(this), this.schedulingRate);
    }

    update(current, payload){
        // timer inactive ?
        if (!this.timer) {
            return;
        }

        super.update(current, payload);

        // trigger synchronous update ?
        // check for throttle time 
        if (this.options.synchronousUpdate && (this.lastRedraw + this.options.throttleTime*2) < Date.now()){
            // force update
            this.render();
        }
    }

    // start the progress bar
    start(total, startValue, payload){
        // progress updates are only visible in TTY mode!
        if (this.options.noTTYOutput === false && this.terminal.isTTY() === false){
            return;
        }

        // add handler to restore cursor settings (stop the bar) on SIGINT/SIGTERM ?
        if (this.sigintCallback === null && this.options.gracefulExit){
            this.sigintCallback = this.stop.bind(this);
            process.once('SIGINT', this.sigintCallback);
            process.once('SIGTERM', this.sigintCallback);
        }

        // save current cursor settings
        this.terminal.cursorSave();

        // hide the cursor ?
        if (this.options.hideCursor === true){
            this.terminal.cursor(false);
        }

        // disable line wrapping ?
        if (this.options.linewrap === false){
            this.terminal.lineWrapping(false);
        }

        // initialize bar
        super.start(total, startValue, payload);

        // redraw on start!
        this.render();
    }

    // stop the bar
    stop(){
        // timer inactive ?
        if (!this.timer) {
            return;
        }
        
        // remove sigint listener
        if (this.sigintCallback){
            process.removeListener('SIGINT', this.sigintCallback);
            process.removeListener('SIGTERM', this.sigintCallback);
            this.sigintCallback = null;
        }

        // trigger final rendering
        this.render();

        // restore state
        super.stop();

        // stop timer
        clearTimeout(this.timer);
        this.timer = null;

        // cursor hidden ?
        if (this.options.hideCursor === true){
            this.terminal.cursor(true);
        }

        // re-enable line wrapping ?
        if (this.options.linewrap === false){
            this.terminal.lineWrapping(true);
        }

        // restore cursor on complete (position + settings)
        this.terminal.cursorRestore();

        // clear line on complete ?
        if (this.options.clearOnComplete){
            this.terminal.cursorTo(0, null);
            this.terminal.clearLine();
        }else{
            // new line on complete
            this.terminal.newline();
        }
    }
}