Read all files from directory and write their contents into one file.

read_and_merge.js

#!/usr/bin/env node

const fs = require('fs');
const os = require('os');
const path = require('path');
const readline = require('readline');

const pkgDir = path.join(os.homedir(), '.emacs.d/scripts/pkg');
const outputFile = path.join(os.homedir(), '.emacs.d/scripts/packages.el');

const writer = fs.createWriteStream(outputFile);
const files = fs.readdirSync(pkgDir);

let pos = 0;

const readAndMerge = file => {
    const filepath = path.join(pkgDir, file);
    const rl = readline.createInterface({
        input: fs.createReadStream(filepath),
        crlfDelay: Infinity,
    });

    rl.on('line', (line) => {
        writer.write(line + '\n');
    });

    rl.on('close', () => {
        const nextFile = files[++pos];
        if (nextFile) {
            readAndMerge(nextFile);
        } else {
            writer.end();
            console.log('Writing file succeeded!');
        }
    });
};

readAndMerge(files[pos]);