add challenge 01 and 02

01-basic-cs/index.js

@@ -5,15 +5,29 @@ const assert = require('assert')
 
 const database = require('./database.json')
 
-const total = 0 // TODO
+let total = 0 // TODO
 
+const hats = _.flatMap(database, 'hats')
+if (hats.length > 0) {
+  const countHatsById = _.countBy(hats, 'id')
+  const topHatsIds = _.chain(countHatsById)
+    .entries()
+    .orderBy(['1', '0'], ['desc', 'asc'])
+    .take(3)
+    .map('0')
+    .value()
+  total = _.sum(_.values(_.pick(countHatsById, topHatsIds)))
+} else {
+  console.log('no hats in db')
+}
 // Throws error on failure
 assert.equal(total, 23, `Invalid result: ${total} != 23`)
 
 console.log('Success!')
 
 /**
  * Time and space complexity in O() notation is:
- *   - time complexity: TODO
- *   - space complexity: TODO
+ *   - time complexity:   O(n)
+ *   - space complexity:  O(n)
+
  */

02-nodejs/controllers/user.js

@@ -0,0 +1,34 @@
+const User = require('../models/User')
+const createCsvWriter = require('csv-writer').createObjectCsvWriter
+const path = require('path')
+
+const csvWriter = createCsvWriter({
+  path: 'bd.csv',
+  header: [
+    { id: '_id', title: '_id' },
+    { id: 'name', title: 'name' },
+    { id: 'email', title: 'email' }
+  ]
+})
+exports.users = async (req, res, next) => {
+  const find = User.find({}).lean().cursor()
+  find.eachAsync(async (user) => {
+    await csvWriter.writeRecords([user])
+    console.log(user.email)
+  })
+    .then(() => {
+      console.log('CSV File generated')
+      res.download(path.join(__dirname, '../../bd.csv'), 'bd.csv', (error) => {
+        if (error) {
+          console.error('Download error in CSV File:', error)
+          res.status(500).send('Download error in CSV File:')
+        } else {
+          console.log('CSV file download OK.')
+        }
+      })
+    })
+    .catch((error) => {
+      console.error('Error to generate CSV file:', error)
+      res.status(500).send('Error to generate CSV file:')
+    })
+}

02-nodejs/index.js

@@ -2,11 +2,12 @@
 
 const express = require('express')
 
-const User = require('./models/User')
+const userRoutes = require('./routes/user')
 
 // Setup Express.js app
 const app = express()
 
 // TODO: everything else
+app.use('/api', userRoutes)
 
-app.listen(3000)
+app.listen(3000, () => console.log('server init'))

02-nodejs/models/User.js

@@ -2,7 +2,7 @@ const mongoose = require('mongoose')
 
 // Setup database
 mongoose.Promise = Promise
-mongoose.connect('mongodb://localhost/mediastream-challenge')
+mongoose.connect('mongodb://localhost:2701/mediastream-challenge')
 
 const User = mongoose.model('User', {
   name: String,

02-nodejs/routes/user.js

@@ -0,0 +1,8 @@
+const express = require('express')
+const router = express.Router()
+
+const { users } = require('../controllers/user')
+
+router.get('/users', users)
+
+module.exports = router