How to use the brotli npm module to compress files

Question

I would like to use this npm module to compress files, but I'm a bit stuck by the documention.

In a linux shell :

npm install brotli # npm@4.1.2 # brotli@1.3.1 

node # v6.9.4

Then inside node:

var fs = require('fs');
var brotli = require('brotli');

brotli.compress(fs.readFileSync('myfile.txt')); // output is numbers

fs.writeFile('myfile.txt.br', brotli.compress(fs.readFileSync('bin.tar')), function(err){ if (!err) { console.log('It works!');}});
"It works!"

But the file is full of numbers too...

I've never used streams and fs like that in node, can someone explains how to deal with this? Thanks!

what exactly are you trying to achieve? If the file looks something like it is correct as you are compressing the buffer that returns from `fs.readFileSync('myfile.txt')` and writing it to another file. If you want to see the decoded buffer you need to decompress it before writing to disk — Gabs, Jan 27 '17 at 15:09
I have to compress files with node (and use the brotli compression as it's cool :) ). In a shell I would have used the "bro" command from the compiled project, but here I don't have access to it. — Ratnoz, Jan 27 '17 at 22:31
if you don't specify an encoding type, node.js will use utf-8 by default. Not sure if this would work but try using binary instead. `fs.writeFile('myfile.txt.br', brotli.compress(fs.readFileSync('bin.tar')), 'binary', function(err){ if (!err) { console.log('It works!');}});` — Gabs, Jan 30 '17 at 13:02
The problem was indeed that I did'nt put any settings/encoding type like `'binary'` or the object in the answer below. — Ratnoz, Sep 19 '19 at 13:39

Ferie · Accepted Answer · 2019-09-20T13:48:55.057

With this simple JS code you are compressing each *.html *.css *.js file inside the folder you choose (in this case /dist)

const fs = require('fs');
const compress = require('brotli/compress');

const brotliSettings = {
    extension: 'br',
    skipLarger: true,
    mode: 1, // 0 = generic, 1 = text, 2 = font (WOFF2)
    quality: 10, // 0 - 11,
    lgwin: 12 // default
};

fs.readdirSync('dist/').forEach(file => {
    if (file.endsWith('.js') || file.endsWith('.css') || file.endsWith('.html')) {
        const result = compress(fs.readFileSync('dist/' + file), brotliSettings);
        fs.writeFileSync('dist/' + file + '.br', result);
    }
});

Thanks! But there is a typo in your import, either write `const brotli = require('brotli');` (line 2) or remove the `brotli.` (line 14). — Ratnoz, Sep 19 '19 at 13:16

How to use the brotli npm module to compress files

1 Answers1