Thursday

Question 1

difference between the postfix and the prefix increment operator

Answer 1

let num = 5;
let result = num++;

console.log(num); // Output: 6 (num was incremented to 6)
console.log(result); // Output: 5 (result holds the initial value of num before the increment)

VERSUS

prefix increment operator —- ++i
the value of the variable is incremented first, and then the updated value is used in the expression or statement

let num = 5;
let result = ++num;

console.log(num); // Output: 6 (num was incremented to 6)
console.log(result); // Output: 6 (result holds the value of the updated num)

https://www.udemy.com/course/the-web-developer-bootcamp/learn/lecture/37338930#overview

Question 2

describe the logic behind using the OR operator to assign value… rewatch reduce video in Colt Steele’s udemy course

Answer 2

the OR operator looks for truthiness in the first statement (an undefined value is falsy & an actual bit of data like a num, string, whatever is truthy) — if that first value is empty, and the second value is truthy, the truth value will get returned

let someInput = “”
const name = someInput || ‘Max’
console.log(name)

const votes = [‘y’, ‘y’, ‘n’, ‘e’, ‘y’, ‘n’, ‘n’, ‘n’, ‘y’];
const tally = votes.reduce((tally, vote) => {
tally[vote] = 1 + (tally[vote] || 0);
return tally;
}, {});

console.log(tally)

Question 3

map
set

Answer 3

Map objects are similar to object literals, but the key types can be any value and they’re actual iterables where you can determine the size of the map.
Sets are a collection of unique values

// Create a Set
const letters = new Set([“a”,”b”,”c”]);

//Convert to an array
Array.from or spread operator

const letters = [“a”,”b”,”c”];
const number = [1, 2, 3, 4];

two ways to convert a set to an array →

const combo1 = […new Set([…letters, …number])];
console.log(combo1); // [‘a’, ‘b’, ‘c’, 1, 2, 3, 4]

const combo2 = Array.from(new Set([…letters, …number]));
console.log(combo2); // [‘a’, ‘b’, ‘c’, 1, 2, 3, 4]

helpful articles :
https://www.w3schools.com/js/js_object_sets.asp
https://www.javascripttutorial.net/es6/javascript-set/

Question 4

how would you average the values in this array using reduce?
const euros = [6, 10, 2];

Answer 4

const avg = euros.reduce((total, currVal) => total += currVal) / euros.length;
console.log(avg);

const sum = euros.reduce((total, currVal) => total += currVal, 0);
let avg = sum / euros.length
console.log(avg);