Add solution for activity 1 for lesson 3

Author: visola

Lesson03/activity_001/.gitignore

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+products.csv

Lesson03/activity_001/index.js

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+const fs = require('fs');
+const http = require('http');
+const JSDOM = require('jsdom').JSDOM;
+
+function extractProducts(document) {
+  const products = [];
+  console.log('Parsing product data...');
+  Array.from(document.getElementsByClassName('item'))
+    .forEach((el) => {
+      process.stdout.write('.');
+      const priceAndUnitElement = el.getElementsByTagName('span')[0];
+      const priceAndUnit = priceAndUnitElement.textContent.split("/");
+
+      const price = priceAndUnit[0].trim().substr(1);
+      const unit = priceAndUnit[1].trim();
+
+      const name = el.getElementsByTagName('a')[0].textContent;
+
+      products.push({ name, price: parseFloat(price), unit });
+    });
+  console.log();
+  console.log(`Found ${products.length} products.`);
+  return products;
+}
+
+function writeCSV(products) {
+  const fileName = 'products.csv';
+
+  console.log(`Writing data to ${fileName}...`);
+  fs.open(fileName, 'w', (error, fileDescriptor) => {
+    if (error != null) {
+      console.error(`Can not write to file: ${fileName}`, error);
+      return;
+    }
+
+    // Write header
+    fs.writeSync(fileDescriptor, 'name,price,unit\n');
+
+    // Write content
+    products.forEach((product) => {
+      const line = `${product.name},${product.price},${product.unit}\n`;
+      fs.writeSync(fileDescriptor, line);
+    });
+    console.log('Done.');
+  });
+}
+
+const page = 'http://localhost:3000';
+console.log(`Downloading ${page}...`);
+const request = http.get(page, (response) => {
+  if (response.statusCode != 200) {
+    console.error(`Error while fetching page ${page}: ${response.statusCode}`);
+    console.error(`Status message: ${response.statusMessage}`);
+    return;
+  }
+
+  let content = '';
+  response.on('data', (chunk) => content += chunk.toString());
+  response.on('close', () => {
+    console.log('Download finished.');
+    const document = new JSDOM(content).window.document;
+    writeCSV(extractProducts(document));
+  });
+});
+
+request.end();