example.js

const express = require('express');

const cars = [{type: 'Nissan', model: 2016}, {type: 'Nissan', model: 2015}, {type: 'Toyota', model: 2016}, {type: 'Kia', model: 2016}]
const punches = [{count: 5, name: 'Arnar'}, {count: 6, name: 'Daníel'}, {count: 10, name: 'Axel'}];

const app = express();
app.get('/goodCarFilter/:year', (req, res) => {
  const filteredCars = cars.filter((car) => {
    return car.model === parseInt(req.params.year);
  })
  res.json(filteredCars);
});

app.get('/badCarFilter/:year', (req, res) => {
  const filteredCars = [];
  cars.forEach((car) => {
    if (car.model === parseInt(req.params.year)) {
      filteredCars.push(car);
    }
  });
  res.json(filteredCars);
});

app.get('/goodPunchedInUsers', (req, res) => {
  const users = punches.map((punch) => {
    return punch.name;
  });
  res.json(users);
});

app.get('/badPunchedInUsers', (req, res) => {
  let users = [];
  for(var i = 0; i < punches.length; i++) {
    users.push(punches[i].name);
  }
  res.json(users);
});

app.get('/goodPunchMap', (req, res) => {
  const punchMap = punches.reduce((accumulated, currentElement) => {
    return Object.assign(accumulated, {[currentElement.name]: currentElement});
  }, {});
  res.json(punchMap);
});

app.get('/badPunchMap', (req, res) => {
  const punchMap = {};
  punches.forEach((punch) => {
    punchMap[punch.name] = punch;
  });
  res.json(punchMap);
});

app.listen(5000)