find_grep.js

#!/usr/bin/env node

const fs = require('fs');
const path = require('path');
const Readable = require('readable-stream').Readable;

function complements(arr, predicate) {
	const out = [[],[]];
	arr.forEach(e => out[Number(!!predicate(e))].push(e));
	return out;
}

function isDirectory(path) {
	return fs.lstatSync(path).isDirectory();
}

function getFiles(root, stream) {

	if (!(stream instanceof Readable)) {
		stream = Readable({objectMode: true});
		stream._read = () => {}; 
	}

	fs.readdir(root, (err, paths) => {
		if (err) throw err;

		paths = paths.map(i => path.join(root, i));
		const [ files, dirs ] = complements(paths, isDirectory);

		files.forEach(f => stream.push(f));
		dirs.forEach(d => getFiles(d, stream));

	});

	return stream;
}

function grep(file, pattern, onMatch) {
	if(file.match(pattern)){
		onMatch(file);
	}
}


getFiles(process.cwd()).on('data', file => {
	grep(file, /package.json$/, fileMatch => {
		console.log(fileMatch);	
	})
});