Javascript / Array

js-array.js

const inventors = [
  { first: 'Albert', last: 'Einstein', year: 1879, passed: 1955 },
  { first: 'Isaac', last: 'Newton', year: 1643, passed: 1727 },
  { first: 'Galileo', last: 'Galilei', year: 1564, passed: 1642 },
  { first: 'Marie', last: 'Curie', year: 1867, passed: 1934 },
  { first: 'Johannes', last: 'Kepler', year: 1571, passed: 1630 },
  { first: 'Nicolaus', last: 'Copernicus', year: 1473, passed: 1543 },
  { first: 'Max', last: 'Planck', year: 1858, passed: 1947 },
  { first: 'Katherine', last: 'Blodgett', year: 1898, passed: 1979 },
  { first: 'Ada', last: 'Lovelace', year: 1815, passed: 1852 },
  { first: 'Sarah E.', last: 'Goode', year: 1855, passed: 1905 },
  { first: 'Lise', last: 'Meitner', year: 1878, passed: 1968 },
  { first: 'Hanna', last: 'Hammarström', year: 1829, passed: 1909 }
];

const people = ['Beck, Glenn', 'Becker, Carl', 'Beckett, Samuel', 'Beddoes, Mick', 'Beecher, Henry', 'Beethoven, Ludwig', 'Begin, Menachem', 'Belloc, Hilaire', 'Bellow, Saul', 'Benchley, Robert', 'Benenson, Peter', 'Ben-Gurion, David', 'Benjamin, Walter', 'Benn, Tony', 'Bennington, Chester', 'Benson, Leana', 'Bent, Silas', 'Bentsen, Lloyd', 'Berger, Ric', 'Bergman, Ingmar', 'Berio, Luciano', 'Berle, Milton', 'Berlin, Irving', 'Berne, Eric', 'Bernhard, Sandra', 'Berra, Yogi', 'Berry, Halle', 'Berry, Wendell', 'Bethea, Erin', 'Bevan, Aneurin', 'Bevel, Ken', 'Biden, Joseph', 'Bierce, Ambrose', 'Biko, Steve', 'Billings, Josh', 'Biondo, Frank', 'Birrell, Augustine', 'Black Elk', 'Blair, Robert', 'Blair, Tony', 'Blake, William'];

// ---------------------------------------------------------------------------

// FILTER / Array.prototype.filter()
// 1. Filter the list of inventors for those who were born in the 1500's
const fifteen = inventors.filter(inventor => (inventor.year >= 1500 && inventor.year < 1600));
console.table(fifteen);


// MAP / Array.prototype.map()
// 2. Give us an array of the inventor first and last names
const fullNames = inventors.map(inventor => `${inventor.first} ${inventor.last}`);
console.log(fullNames);


// SORT / Array.prototype.sort()
// 3. Sort the inventors by birthdate, oldest to youngest
// const ordered = inventors.sort(function(a, b) {
//   if(a.year > b.year) {
//     return 1;
//   } else {
//     return -1;
//   }
// });
const ordered = inventors.sort((a, b) => a.year > b.year ? 1 : -1);
console.table(ordered);


// REDUCE / Array.prototype.reduce()
// 4. How many years did all the inventors live?
const totalYears = inventors.reduce((total, inventor) => {
    return total + (inventor.passed - inventor.year);
}, 0);
console.log(totalYears);


// SORT / Array.prototype.sort()
// 5. Sort the inventors by years lived
const oldest = inventors.sort(function(a, b) {
  const lastInventor = a.passed - a.year;
  const nextInventor = b.passed - b.year;
  return lastInventor > nextInventor ? -1 : 1;
});
console.table(oldest);


// SORT / Array.prototype.sort()
// 6. create a list of Boulevards in Paris that contain 'de' anywhere in the name
// https://en.wikipedia.org/wiki/Category:Boulevards_in_Paris
// const category = document.querySelector('.mw-category');
// const links = Array.from(category.querySelectorAll('a'));
// const de = links
//             .map(link => link.textContent)
//             .filter(streetName => streetName.includes('de'));


// SORT / Array.prototype.sort()
// 7. sort Exercise
// Sort the people alphabetically by last name
const alpha = people.sort((lastOne, nextOne) => {
  const [aLast, aFirst] = lastOne.split(', ');
  const [bLast, bFirst] = nextOne.split(', ');
  return aLast > bLast ? 1 : -1;
});
console.log(alpha);


// REDUCE / Array.prototype.reduce()
// 8. Reduce Exercise
// Sum up the instances of each of these
const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck', 'pogostick'];
const transportation = data.reduce(function(obj, item) {
  if (!obj[item]) {
    obj[item] = 0;
  }
  obj[item]++;
  return obj;
}, {});
console.log(transportation);

// ################################################################################

const people = [
  { name: 'Wes', year: 1988 },
  { name: 'Kait', year: 1986 },
  { name: 'Irv', year: 1970 },
  { name: 'Lux', year: 2015 },
];

const comments = [
  { text: 'Love this!', id: 523423 },
  { text: 'Super good', id: 823423 },
  { text: 'You are the best', id: 2039842 },
  { text: 'Ramen is my fav food ever', id: 123523 },
  { text: 'Nice Nice Nice!', id: 542328 }
];

// 1. SOME()
// Some and Every Checks
// Array.prototype.some() // is at least one person 19?
// const isAdult = people.some(function(person) {
//   const currentYear = (new Date()).getFullYear();
//   if(currentYear - person.year >= 19) {
//     return true;
//   }
// });
const isAdult = people.some(person => ((new Date()).getFullYear()) - person.year >= 19);
console.log({isAdult});


// 2.EVERY()
// Array.prototype.every() // is everyone 19?
const allAdults = people.every(person => ((new Date()).getFullYear()) - person.year >= 19);
console.log({allAdults});


// 3.FIND()
// Array.prototype.find()
// Find is like filter, but instead returns just the one you are looking for
// find the comment with the ID of 823423
const comment = comments.find(comment => comment.id === 823423);
console.log(comment);


// 4.FINDINDEX()
// Array.prototype.findIndex()
// Find the comment with this ID
// delete the comment with the ID of 823423
const index = comments.findIndex(comment => comment.id === 823423);
console.log(index);
// comments.splice(index, 1);
const newComments = [
  ...comments.slice(0, index),
  ...comments.slice(index + 1)
];