Node js speed up puppeteer html to pdf - html

Question

I have a node js application that creates dynamic content which I want users to download.
static async downloadPDF(res, html, filename) {
const puppeteer = require('puppeteer');
const browser = await puppeteer.launch({
headless: true
});
const page = await browser.newPage()
await page.setContent(html, {
waitUntil: 'domcontentloaded'
})
const pdfBuffer = await page.pdf({
format: 'A4'
});
res.set("Content-Disposition", "attachment;filename=" + filename + ".pdf");
res.setHeader("Content-Type", "application/pdf");
res.send(pdfBuffer);
await browser.close()
}
Is there a way to speed up the whole process since it takes about 10 seconds to create a pdf file of size about 100kb?
I read somewhere that I can launch the headless browser once then I will only be creating a new page instead of launching a browser every time I request for the file.
I cannot find out a correct way of doing it.

Answer 1

You could move page creation to a util and hoist it to re-use it.
const puppeteer = require('puppeteer');
let page;
const getPage = async () => {
if (page) return page;
const browser = await puppeteer.launch({
headless: true,
});
page = await browser.newPage();
return page;
};
.
const getPage = require('./getPage');
static async downloadPDF(res, html, filename) {
const page = await getPage()
}

Answer 2

Yes, no reason to launch browser every time. You can set puppeter to call new url and get content. Without every time launching, it would be more faster.
How implement this ? Cut your function to three steps :
Create a browser instance. No matter headless or not. If you run app in X environment, you can launch a window, to see what your puppetter do
Create a function code, that will do main task in cycle.
After block is done, call await page.goto(url) ( where "page" is the instance of browser.newPage() ) and run your function again.
This is one of possible solution in function style code :
Create a instnces :
const browser = await puppeteer.launch( {'headless' : false });
const page = await browser.newPage();
page.setViewport({'width' : 1280, 'height' : 1024 });
I put it in realtime async function like (async ()=>{})();
Gets a data
Im my case, a set of urls was in mongo db, after getting it, I had ran a cycle :
for( const entrie of entries)
{
const url = entrie[1];
const id = entrie[0];
await get_aplicants_data(page,url,id,collection);
}
In get_aplicants_data() I had realized a logic according a loaded page :
await page.goto(url); // Going to url
.... code to prcess page data
Also you can load url in cycle and then put in your logic
Hope I have given you some help )