Psst: have a look at the JavaScript Console 💁
Get your shorts on - this is an array workout!
// Some data we can work with
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 = [
'Bernhard, Sandra', 'Bethea, Erin', 'Becker, Carl', 'Bentsen, Lloyd', 'Beckett, Samuel', 'Blake, William', 'Berger, Ric', 'Beddoes, Mick', 'Beethoven, Ludwig',
'Belloc, Hilaire', 'Begin, Menachem', 'Bellow, Saul', 'Benchley, Robert', 'Blair, Robert', 'Benenson, Peter', 'Benjamin, Walter', 'Berlin, Irving',
'Benn, Tony', 'Benson, Leana', 'Bent, Silas', 'Berle, Milton', 'Berry, Halle', 'Biko, Steve', 'Beck, Glenn', 'Bergman, Ingmar', 'Black, Elk', 'Berio, Luciano',
'Berne, Eric', 'Berra, Yogi', 'Berry, Wendell', 'Bevan, Aneurin', 'Ben-Gurion, David', 'Bevel, Ken', 'Biden, Joseph', 'Bennington, Chester', 'Bierce, Ambrose',
'Billings, Josh', 'Birrell, Augustine', 'Blair, Tony', 'Beecher, Henry', 'Biondo, Frank'
];
// 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);
// 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);
// 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);
// 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);
// 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);
// 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'));
// 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);
// 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);
Psst: have a look at the JavaScript Console 💁
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 }
];
// 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});
// Array.prototype.every() // is everyone 19?
const allAdults = people.every(person => ((new Date()).getFullYear()) - person.year >= 19);
console.log({allAdults});
// 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);
// 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)
];