Saving Presentations

Several methods are available when generating a presentation.

• All methods return a Promise
• Working examples are available under /PptxGenJS/demos

Saving as a File (writeFile)

Save the presentation as a PowerPoint .pptx file.

• In browser-based apps, this triggers a download using the correct pptx MIME-type.
• In Node.js, it saves to disk via the native fs module.

Write File Props (WriteFileProps)

Option	Type	Default	Description
compression	boolean	false	apply zip compression (exports take longer but saves signifcant space)
fileName	string	'Presentation.pptx'	output filename

Write File Example

// For simple cases, you can omit `then`
pptx.writeFile({ fileName: 'Browser-PowerPoint-Demo.pptx' });

// Using Promise to determine when the file has actually completed generating
pptx.writeFile({ fileName: 'Browser-PowerPoint-Demo.pptx' });
    .then(fileName => {
        console.log(`created file: ${fileName}`);
    });

Generating Other Formats (write)

Generate the presentation in various formats (e.g., base64, arraybuffer) — useful for uploading to cloud storage or handling in-memory.

Write Props (WriteProps)

Option	Type	Default	Description
compression	boolean	false	apply zip compression (exports take longer but save significant space)
outputType	string	blob	'arraybuffer', 'base64', 'binarystring', 'blob', 'nodebuffer', 'uint8array'

Write Output Types

outputType	Description
blob	Default for browsers
arraybuffer	Often used with WebAssembly or binary tools
base64	Useful for uploads to APIs like Google Drive
nodebuffer	Use in Node.js with fs.writeFile()

Write Example

pptx.write({ outputType: "base64" })
    .then((data) => {
        console.log("write as base64: Here are 0-100 chars of `data`:\n");
        console.log(data.substring(0, 100));
    })
    .catch((err) => {
        console.error(err);
    });

Streaming in Node.js (stream)

Returns the presentation as a binary string, suitable for streaming in HTTP responses or writing directly to disk in Node.js environments.

Stream Example

// SRC: https://github.com/gitbrent/PptxGenJS/blob/master/demos/node/demo_stream.js
// HOW: using: `const app = express();``
pptx.stream()
    .then((data) => {
        app.get("/", (req, res) => {
            res.writeHead(200, { "Content-disposition": "attachment;filename=" + fileName, "Content-Length": data.length });
            res.end(new Buffer(data, "binary"));
        });
        app.listen(3000, () => {
            console.log("PptxGenJS Node Stream Demo app listening on port 3000!");
            console.log("Visit: http://localhost:3000/");
            console.log("(press Ctrl-C to quit demo)");
        });
    })
    .catch((err) => {
        console.log("ERROR: " + err);
    });

Restricted / Sandbox Runtimes

Compressed export (stream({ compression: true }), or any write/writeFile DEFLATE path) works in hardened runtimes such as a Node vm sandbox that omit setImmediate. The library polyfills globalThis.setImmediate/clearImmediate from setTimeout/clearTimeout only when they are absent, so a real Node setImmediate is never replaced. For a sandbox-safe write, use write({ outputType: "nodebuffer" }) and hand the buffer to your own fs.writeFileSync. The library guarantees no use of eval, new Function, or WebAssembly instantiation — it works in contexts where codeGeneration: { strings: false, wasm: false } is enforced.

Saving Multiple Presentations

In the Browser

Each new presentation should use a fresh new PptxGenJS() instance to avoid reusing slides or metadata.

let pptx = null;

// Presentation 1:
pptx = new PptxGenJS();
pptx.addSlide().addText("Presentation 1", { x: 1, y: 1 });
pptx.writeFile({ fileName: "PptxGenJS-Browser-1" });

// Presentation 2:
pptx = new PptxGenJS();
pptx.addSlide().addText("Presentation 2", { x: 1, y: 1 });
pptx.writeFile({ fileName: "PptxGenJS-Browser-2" });

In Node.js

• See demos/node/demo.js for a working demo with multiple presentations, promises, etc.
• See demos/node/demo_stream.js for a working demo using streaming

import pptxgen from "pptxgenjs";

// Presentation 1:
let pptx1 = new pptxgen();
pptx1.addSlide().addText("Presentation 1", { x: 1, y: 1 });
pptx1.writeFile({ fileName: "PptxGenJS-NodePres-1" });

// Presentation 2:
let pptx2 = new pptxgen();
pptx2.addSlide().addText("Presentation 2", { x: 1, y: 1 });
pptx2.writeFile({ fileName: "PptxGenJS-NodePres-2" });