@pilotlab/lux-debug/src/logCursor.ts

A luxurious user experience framework, developed by your friends at Pilot.

let readline = require('readline'); // built-in node package
import LogConsole from './logConsole';


export class LogCursor {
    constructor(console:LogConsole) {
        this._console = console;
    }


    private _console:LogConsole;
    private _readline:any;


    setLine(value:number):LogCursor { return this.setPosition(undefined, value); }
    setColumn(value:number):LogCursor { return this.setPosition(value, undefined); }
    setPosition(x:number, y:number):LogCursor { readline.cursorTo(this._console.stream, x, y); return this; }
    move(x:number, y:number):LogCursor { readline.moveCursor(this._console.stream, x, y); return this; }
    up(value:number = 1):LogCursor { return this.move(0, -Math.abs(value)); }
    down(value:number = 1):LogCursor { return this.move(0, Math.abs(value)); }
    left(value:number = 1):LogCursor { return this.move(-Math.abs(value), 0); }
    right(value:number = 1):LogCursor { return this.move(Math.abs(value), 0); }


    hide() {
        this._readline = readline.createInterface({
            input: process.stdin,
            output: process.stdout
        });

        if (this._readline) this._readline.pause(); // This locks down keyboard input.
        this._console.stream.write(this._encode('[?25l')); // From Charm
        return this;
    }


    show() {
        if (this._readline) {
            /// Don't call this._readline.resume() as it interrupts testing.
            /// Instead, just close the interface.
            this._readline.close();
        }

        this._console.stream.write(this._encode('[?25h')); // From Charm
        return this;
    }


    /// From Charm
    private _encode(value:string):Buffer {
        return new Buffer([0x1b].concat(value.split('').map((value:string) => value.charCodeAt(0))));
    };
} // End class


export default LogCursor;