ChangelogApp/main.js

const { app, BrowserWindow } = require('electron/main')

let progressInterval

function createWindow () {
    const win = new BrowserWindow({
        width: 1000,
        height: 800
    })

    win.loadFile('index.html')

    const INCREMENT = 0.03
    const INTERVAL_DELAY = 100 // ms

    let c = 0
    progressInterval = setInterval(() => {
        win.setProgressBar(c)

        if (c < 2) {
            c += INCREMENT
        } else {
            c = (-INCREMENT * 5)
        }
    }, INTERVAL_DELAY)
}

app.whenReady().then(createWindow)

// before the app is terminated, clear both timers
app.on('before-quit', () => {
    clearInterval(progressInterval)
})

app.on('window-all-closed', () => {
    if (process.platform !== 'darwin') {
        app.quit()
    }
})

app.on('activate', () => {
    if (BrowserWindow.getAllWindows().length === 0) {
        createWindow()
    }
})