Siteimprove test

index.js

'strict mode';

/**
 * > You choose programming language, any external libraries
 * > and strategi for implementation.
 * > You should build a solution from scratch.
 *
 * I chose Javascript that work on a server (NodeJS)
 */

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

const pattern = /Section \d+ Refresh/;
const inputPath = './input';
const files = fs.readdirSync(inputPath);

const ids = [];
const promises = [];

/**
 * > Assume that there's no upper limit on the length of an inputfile.
 *
 * In this case, I'm reading a file line by line, to prevent memory limit server error
 */
files.forEach((file) => {
    var promise = new Promise((resolve) => {
        const filePath = path.resolve(__dirname, inputPath, file);
        const rl = readline.createInterface(fs.createReadStream(filePath), new stream);

        rl.on('line', (line) => {
            /**
             * > Scan or search through a set of textfiles in the format described above
             * > after a given search pattern (in regular expression syntax).
             * > If a linie in an input file matches the pattern, return the id of the
             * > matching line. Neither the name of the file, the content of the line
             * > or the order of the resulting id's matter.
             *
             * I had strict rules about the file format from your side.
             * So I'm checking the line "as it is"
             * to avoid split() or substr() operations and save the CPU
             */
            if (!line.match(pattern)) return;

            const id = line.substr(0, line.indexOf(':'));
            ids.push(id);
        });

        rl.on('close', () => {
            resolve();
        });
    });

    promises.push(promise);
});

/**
 * > Try to achieve optimal ressource (min IO, min RAM, max CPU) utilization,
 * > by eg. threading or other strategies of your choice.
 * 
 * I used an async aproach to improve speed of process
 */
Promise.all(promises).then(() => {
    console.log('Input:', files.join(' '));
    console.log('Search:', pattern);
    console.log('Results:', ids.join());
});