mouseboard.js

const robot = require('robot-js');
const { Keyboard, Mouse } = robot;

const keymap = {
    I: [0, -1],
    J: [-1, 0],
    L: [1, 0],
    K: [0, 1],
    E: [0, -1],
    S: [-1, 0],
    F: [1, 0],
    D: [0, 1],
};

const speed = 1;
const delay = 0;

const isMouseModeOn = state =>
    state[robot.KEY_RSHIFT] && state[robot.KEY_LSHIFT];

const m = Mouse();

(async function main() {
    while (true) {
        const kstate = Keyboard.getState();
        if (isMouseModeOn(kstate)) {
            const delta = [0, 0];
            for (let k in keymap) {
                if (kstate[robot[`KEY_${k}`]]) {
                    delta[0] += keymap[k][0];
                    delta[1] += keymap[k][1];
                }
            }
            const mstate = Mouse.getPos();
            mstate.x += delta[0] * speed;
            mstate.y += delta[1] * speed;
            Mouse.setPos(mstate);
            
            if (kstate[robot.KEY_SPACE]) {
                m.click(robot.BUTTON_LEFT);
            }
        }
        await new Promise(r => setTimeout(r, delay));
    }
})();