Detect docx file type from buffer.
Checks for 'PK\x03\x04\x14\x00\x06\x00'
at the start of a file buffer.
npm install is-docx
const fs = require('fs');
const isDocx = require('is-docx');
const file = fs.readFileSync('example.docx');
console.log(isDocx(file)); // > true