the-honk/challenges/euler/scripts/generate.js

const inquirer = require('inquirer');
const fs = require('fs');
const path = require('path');
const { root, src, thoughts: thoughtsDir } = require('../constants');
const axios = require('axios');
const cheerio = require('cheerio');

const readmeContent = fs.readFileSync(path.join(root, 'readme.md')).toString();

const problems = readmeContent.match(/^-   \[.] (?:\[(.*)\]|(.*))/gm).map(res => {
    const sanitised = res.substring(8).replace('[', '').replace(']', '');
    return sanitised.match(/[0-9]* - (.*)/)[1];
});

inquirer
    .prompt([
        {
            name: 'problemNumber',
            message: 'Which problem would you like to solve?',
            type: 'number',
            validate: input => {
                input = parseInt(input);

                if (input > 100) return 'Please make sure you choose a number between 1 and 100!';
                else {
                    let alreadyGenerated = false;
                    fs.readdirSync(src).forEach(file => {
                        if (file.startsWith(input)) alreadyGenerated = true;
                    });

                    if (alreadyGenerated)
                        return 'Please choose a problem you have not already completed!';
                    else return true;
                }
            }
        },
        {
            name: 'thoughts',
            message: 'Should I generate a thoughts document for you?',
            type: 'confirm',
            default: false
        }
    ])
    .then(({ problemNumber, thoughts }) => {
        const fileName = `${problemNumber} - ${problems[problemNumber - 1]}`;

        // Fetch the problem data off of projecteuler.net
        axios.get(`https://projecteuler.net/problem=${problemNumber}`).then(({ data }) => {
            const $ = cheerio.load(data);
            const problemContent = $('.problem_content')
                .text()
                .trim()
                .split('\n')
                .map(r => `// ${r}`)
                .join('\n');

            // Generate the source file
            fs.writeFileSync(
                path.join(src, `${fileName}.ts`),
                `${problemContent}
export = {};

// Output
console.log();`
            );

            // Generate the thoughts file
            if (thoughts) fs.writeFileSync(path.join(thoughtsDir, `${fileName}.md`), '');

            // Check it off in the readme
            const regex = new RegExp(`   \\[.\\] ${problemNumber} - .*`);
            const match = readmeContent.match(regex);

            let newLine = `   [x] [${match[0].replace('[ ]', '').trim()}](src/${encodeURIComponent(
                fileName
            )}.ts)`;

            if (thoughts)
                newLine += `\n    -   [Thoughts](thoughts/${encodeURIComponent(fileName)}.md)`;

            const newContent = readmeContent.replace(regex, newLine);

            fs.writeFileSync(path.join(root, 'readme.md'), newContent);
        });
    });