Create your first .pptx file with pptxgenjs

Time for the payoff every later lesson builds on: a file that opens in PowerPoint. We won't write the file format ourselves. A .pptx is a zip archive of dozens of XML files, and the open-source library pptxgenjs writes all of them for us.

The four steps

const pptx = new PptxGenJS();          // 1. a presentation
pptx.layout = "LAYOUT_16x9";           //    10 × 5.625 inches

const slide = pptx.addSlide();         // 2. a slide

slide.addText("Hello", {               // 3. things on the slide
  x: 0.75, y: 2, w: 8.5, h: 1.25,      //    inches
  fontSize: 40, bold: true,            //    points
  color: "1F2937",                     //    hex, no #
});

return pptx.write({ outputType: "base64" });  // 4. the file

• Positions are in inches and font sizes in points, exactly as in the inches and points lesson.
• Colors are six hex digits without a #. "#1F2937" makes pptxgenjs write a broken color.
• write() is asynchronous: it zips the files, so it returns a promise.

Why base64?

A .pptx is binary data. Base64 turns bytes into plain text, which is easy to return from a function, send inside JSON to a browser, or turn back into bytes to save. In the playground, when your code returns one, a Download button appears.