Automatic display brightness based on whether AC is connected

auto-brightness.js

const systeminformation = require('systeminformation');
const osxBrightness = require('osx-brightness');

let lastIsAcConnectedState = null;

systeminformation.battery(data => {
    lastIsAcConnectedState = data.acconnected;
    setInterval(() => {
        systeminformation.battery(data => {
            if (data.acconnected) {
                if (lastIsAcConnectedState === false) {
                    lastIsAcConnectedState = true;
                    osxBrightness.set(1);
                }
            } else {
                if (lastIsAcConnectedState === true) {
                    lastIsAcConnectedState = false;
                    osxBrightness.set(0.75);
                }
            }
        });
    }, 30 * 1000);
});