Hackforge Academy

Explanation

JavaScript does not have a built-in data structure called 'List' like Python or Java. In JavaScript, arrays are commonly used to represent lists. An array stores an ordered collection of values and provides many methods to manipulate the data such as push(), pop(), shift(), unshift(), map(), filter(), and forEach().

Code:

const list = [10, 20, 30, 40];

// add element
list.push(50);

// remove last element
list.pop();

// iterate list
list.forEach(item => {
  console.log(item);
});

console.log(list);

Explanation

Adds one or more elements to the end of an array and returns the new length.

Code:

const list = [10,20,30,40];
list.push(50);
console.log(list); 
// [10,20,30,40,50]

Explanation

Removes the last element from an array and returns that element.

Code:

const list = [10,20,30,40];
const removed = list.pop();
console.log(removed); // 40
console.log(list); // [10,20,30]

Explanation

Removes the first element from an array and returns that element.

Code:

const list = [10,20,30,40];
const removed = list.shift();
console.log(removed); // 10
console.log(list); // [20,30,40]

Explanation

Adds one or more elements to the beginning of an array and returns the new length.

Code:

const list = [10,20,30,40];
list.unshift(5);
console.log(list); // [5,10,20,30,40]

Explanation

Creates a new array by applying a function to each element of the original array.

Code:

const list = [10,20,30,40];
const result = list.map(num => num * 2);
console.log(result); // [20,40,60,80]

Explanation

Creates a new array with elements that pass a given condition.

Code:

const list = [10,20,30,40];
const result = list.filter(num => num > 20);
console.log(result); // [30,40]

Explanation

Executes a function for each element in the array. It does not return a new array.

Code:

const list = [10,20,30,40];
list.forEach(num => {
  console.log(num);
});