Shows version of .CRX file (chromium extensions). JavaScript version.

crxver.js

#!/usr/bin/env node
const fs = require('fs');

const filePath = process.argv[2];
if(!filePath) {
        console.error('No file specified.\nUsage:\n\tnode crxver.js my-extensions.crx\n');
        process.exit(-1);
}

const buf = fs.readFileSync(filePath);

const VERSION_POS_BYTE_OFFSET = 4;
const VERSION_LENGTH_BYTE = 1;

const type = buf.subarray(0, 4).toString('ascii');
const version = buf.readIntBE(VERSION_POS_BYTE_OFFSET, VERSION_LENGTH_BYTE).toString(16);

console.log('File type:\t', type);
console.log('Version:\t', version);

Usage:

node crxver.js my-extensions.crx

Output:

File type:	 Cr24
Version:	 3

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