Pptxgenjs: Node module appends to last generated PPT on save()

[alexanderpepper]

I'm using the node module in a Sails.js project.

The first time I generate a PPT, everything looks good. When I generate a second PPT, the output file contains both presentations. A third call to .save() will produce a file with all three presentations.

I've tried requiring the module each time my generating method is called instead of a single time at the top of the file, but that's not working.

Is the library caching the last presentation? Is there any way to clear it?

[gitbrent]

Hi @alexanderpepper

Thanks for opening an issue. I was not able to reproduce this, however, I was using the same name for the output file which I can see might cause the Zip library to append instead of creating a new one.

I've now added a timestamp to the output filename so that this situation will be avoided.

Let me know if the issue persists.

[alexanderpepper]

Hi @gitbrent

Thanks for looking into it. I've tried using different filename and also tried deleting the old PPT before generating the new one. Neither worked.

Here's a Node script that reproduces the issue (and possibly another issue).

var pptx1 = require('pptxgenjs');

var slide = pptx1.addNewSlide();
slide.addText('Hello World!', { x:1.5, y:1.5, font_size:18, color:'363636' });
pptx1.save('Sample Presentation 1');

var pptx2 = require('pptxgenjs');

var slide2 = pptx2.addNewSlide();
slide.addText('Hello Again!', { x:1.5, y:1.5, font_size:18, color:'9A0000' });
pptx2.save('Sample Presentation 2');

[shivampadaliya]

Hi @alexanderpepper

I also had this issue and fixed it by invalidating cache.

delete require.cache[require.resolve('pptxgenjs')];
pptx1 = require('pptxgenjs');

That should solve your issue.

[alexanderpepper]

Excellent. That fixed it. Thanks @shivampadaliya

[gitbrent]

Ohhh, I completely misunderstood what you @alexanderpepper reported.

This is the expected behavior. The act of saving a Presentation doesn't automatically clear all the existing Slides, which is what is sounds like you were expecting. You can continue to .add* lots of things to the same pptx variable instance and it'll continue to accumulate Slides.

In order to generate new, unique Presentations, one would just grab a new instance of the library, which is what @shivampadaliya 's solution provides.

var pptx = new PptxGenJS();

pptx.addNewSlide().addText('pres 1', {x:1, y:1});
pptx.save('PptxGenJS-Sandbox-1');

// "Reset" pptx 
pptx = new PptxGenJS();

pptx.addNewSlide().addText('pres 2', {x:1, y:1});
pptx.save('PptxGenJS-Sandbox-2');

Thanks to you both for reporting this and helping document the behavior.

[gabrielm0]

I've made a reset function to reset the pptx object like this:

this.reset = function() { gObjPptx = {}; gObjPptx.title = 'PptxGenJS Presentation'; gObjPptx.fileName = 'Presentation'; gObjPptx.fileExtn = '.pptx'; gObjPptx.pptLayout = LAYOUTS['LAYOUT_16x9']; gObjPptx.slides = []; };

and call this function to reset the last generated ppt...

[ArturFedorov]

This works if you do it on client with Angular for example;
import pptx from "pptxgenjs";

let PptxGenJS=Object.getPrototypeOf(pptx).constructor;
let presentation=new PptxGenJS();

It resets the object

[gitbrent]

This issue is resolved now (v 2.0.0).

See Issue #83