Display multiple progress bars in an Electron window.

• Full Typescript support, including event types
• Zero runtime dependencies
• Full documentation
• Example playground to try it out in an Electron app
• Progress bars are displayed in a single window (or multiple windows if you prefer)
• ProgressWindows and ProgressItems are event emitters
• Progress items can be added and removed dynamically
• Progress items can be updated dynamically
• Progress bars can be indeterminate (no value) or determinate (with value)
• Window can adjust size automatically as progress items are added and removed
• Automatically close window when all progress items are complete (or not)
• Configure default options for ProgressWindow and ProgressItem instances
• Choose whether individual progress bars are removed from window when complete
• Individual progress bars can be paused and resumed, sending 'pause' event
• Progress bars can be cancelled, sending 'will-cancel' and 'cancelled' event
• Ability to add custom CSS or HTML (in title or detail)
• Ability to fully customize the Electron BrowserWindow options
• Full test coverage

npm install @spaceagetv/electron-progress-window

The progress page is loaded from a data: URL, which has an opaque origin. Together with the window's sandbox and webSecurity settings, that means the page cannot fetch subresources of any kind — not file://, not a relative path, not a custom protocol registered by your app. Any url() in the css option pointing at a file will silently fail to load.

Use inlineAsset() to embed the file in the stylesheet instead:

const path = require('path')
const { ProgressWindow, inlineAsset } = require('@spaceagetv/electron-progress-window')

const brandFont = inlineAsset(path.join(__dirname, 'assets/brand.woff2'))

ProgressWindow.configure({
  css: `
    @font-face {
      font-family: 'Brand';
      src: url('${brandFont}') format('woff2');
    }
    html {
      --font-family: 'Brand', sans-serif;
    }
  `,
})

The media type is inferred from the file extension for common font and image formats; pass it as a second argument for anything else.

Inlined assets end up in the page URL, so watch the total size — a full variable font is roughly 75 KB of base64 before encodeURIComponent expands +, / and =. Subsetting a font to the characters you actually use makes a large difference.

The window's colors, shadows and hover states are driven by CSS custom properties. Pass a stylesheet through the css option, or set individual properties per item with cssVars — see itemCssMap for the full list of what is configurable. Anything not covered there can still be overridden with an ordinary CSS rule through the css option.

Design systems usually scope their token file to a selector such as [data-theme="dark"] or .theme-dark. Use htmlAttributes or bodyClass to put that selector on the progress page's root element, so the token file can be injected verbatim instead of being rewritten:

ProgressWindow.configure({
  htmlAttributes: { 'data-theme': 'dark' },
  // or: bodyClass: 'theme-dark',
  css: fs.readFileSync('./design-system/tokens.css', 'utf8'),
})

To flatten the default glossy progress bar:

ProgressWindow.configure({
  css: `
    html {
      --progress-shadow: none;
      --indicator-shadow: none;
    }
  `,
})

const { ProgressWindow } = require('@spaceagetv/electron-progress-window')

// Configure the settings for ProgressWindow
ProgressWindow.configure({
  closeOnComplete: true,
  focusOnAdd: true,
  windowOptions: { // these are Electron BrowserWindow options
    title: 'Progress',
    width: 300,
    height: 60,
    backgroundColor: '#f00',
  },
})

async function somethingThatTakesTime(progressCallback) {
  const state = {
    paused: false,
    cancelled: false,
  }
  for (let i = 0; i < 100; i++) {
    while (state.paused && !state.cancelled) {
      await new Promise((resolve) => setTimeout(resolve, 100))
    }
    if (state.cancelled) {
      break
    }
    await new Promise((resolve) => setTimeout(resolve, 100))
    progressCallback(Math.round((i + 1) / 100 * 100))
  }
  const setPause = (isPaused) => {
    state.paused = isPaused
  }
  const cancel = () => {
    state.cancelled = true
  }
  return { setPause, cancel }
}

async function start() {
  const progressItem = await ProgressWindow.addItem({
    title: 'Something that takes time',
    detail: '0% complete',
    value: 0,
    maxValue: 100,
    pauseable: true,
    cancellable: true,
  })

  const updateProgress = (progress) => {
    progressItem.value = progress
    progressItem.detail = `${progress}% complete`
  }

  const { setPause, cancel } = await somethingThatTakesTime(updateProgress)

  progressItem.on('paused', (isPaused) => {
    setPause(isPaused)
  })
  progressItem.on('cancelled', () => {
    cancel()
  })
}

start()