[1, 2, 3].push(4); // [1, 2, 3, 4]

[1, 2, 3].pop(); // [1, 2]

[1, 2, 3].shift(); // [2, 3]

[1, 2, 3].unshift(0); // [0, 1, 2, 3]

['a', 'b'].concat('c'); // ['a', 'b', 'c']

['a', 'b', 'c'].join('-'); // a-b-c

['a', 'b', 'c'].slice(1); // ['b', 'c']

['a', 'b', 'c'].indexOf('b'); // 1

['a', 'b', 'c'].includes('c'); // true

[3, 5, 6, 8].find((n) => n % 2 === 0); // 6

[2, 4, 3, 5].findIndex((n) => n % 2 !== 0); // 2

[3, 4, 8, 6].map((n) => n * 2); // [6, 8, 16, 12]

[1, 4, 7, 8].filter((n) => n % 2 === 0); // [4, 8]

[2, 4, 3, 7].reduce((acc, cur) => acc + cur); // 16

[2, 3, 4, 5].every((x) => x < 6); // true

[3, 5, 6, 8].some((n) => n > 6); // true

[1, 2, 3, 4].reverse(); // [4, 3, 2, 1]

[3, 5, 7, 8].at(-2); // 7

27

javascript array functions

concat(arr1,[...]) // Joins two or more arrays, and returns a copy of the joined arrays

copyWithin(target,[start],[end]) // Copies array elements within the array, to and from specified positions

entries() // Returns a key/value pair Array Iteration Object

every(function(currentval,[index],[arr]),[thisVal]) // Checks if every element in an array pass a test

fill(val,[start],[end]) // Fill the elements in an array with a static value

filter(function(currentval,[index],[arr]),[thisVal]) // Creates a new array with every element in an array that pass a test

find(function(currentval,[index],[arr]),[thisVal]) // Returns the value of the first element in an array that pass a test

findIndex(function(currentval,[index],[arr]),[thisVal]) // Returns the index of the first element in an array that pass a test

forEach(function(currentval,[index],[arr]),[thisVal]) // Calls a function for each array element

from(obj,[mapFunc],[thisVal]) // Creates an array from an object

includes(element,[start]) // Check if an array contains the specified element

indexOf(element,[start]) // Search the array for an element and returns its position

isArray(obj) // Checks whether an object is an array

join([seperator]) // Joins all elements of an array into a string

keys() // Returns a Array Iteration Object, containing the keys of the original array

lastIndexOf(element,[start]) // Search the array for an element, starting at the end, and returns its position

map(function(currentval,[index],[arr]),[thisVal]) // Creates a new array with the result of calling a function for each array element

pop() // Removes the last element of an array, and returns that element

push(item1,[...]) // Adds new elements to the end of an array, and returns the new length

reduce(function(total,currentval,[index],[arr]),[initVal]) // Reduce the values of an array to a single value (going left-to-right)

reduceRight(function(total,currentval,[index],[arr]),[initVal]) // Reduce the values of an array to a single value (going right-to-left)

reverse() // Reverses the order of the elements in an array

shift() // Removes the first element of an array, and returns that element

slice([start],[end]) // Selects a part of an array, and returns the new array

some(function(currentval,[index],[arr]),[thisVal]) // Checks if any of the elements in an array pass a test

sort([compareFunc]) // Sorts the elements of an array

splice(index,[quantity],[item1,...]) // Adds/Removes elements from an array

toString() // Converts an array to a string, and returns the result

unshift(item1,...) // Adds new elements to the beginning of an array, and returns the new length

valueOf() // Returns the primitive value of an array

Array:

.length - Property that represents the number of elements in an array.

.concat() - Joins two or more arrays and returns a new array.

.indexOf() - Returns the index of the first occurrence of a specified element.

.lastIndexOf() - Returns the index of the last occurrence of a specified element.

.push() - Adds one or more elements to the end of an array.

.pop() - Removes the last element from an array.

.shift() - Removes the first element from an array.

.unshift() - Adds one or more elements to the beginning of an array.

.slice() - Extracts a portion of an array into a new array.

.splice() - Changes the contents of an array by removing or replacing existing elements.

.forEach() - Calls a function for each element in an array.

.map() - Creates a new array with the results of calling a provided function on every element.

.filter() - Creates a new array with elements that pass a test.

.reduce() - Applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value.

//ADD ELEMENTS

//PUSH - adds elements to the END OF ARRAY

const friends = ["Zizi", "Ioseb", "Maiko"];

const newLength = friends.push("Karina");

console.log(friends); //["Zizi", "Ioseb", "Maiko"]

console.log(newLenght); //["Zizi", "Ioseb", "Maiko", "Karina"]

​

//UNSHIFT - add elements to BEGINNING OF THE ARRAY

friends.unshift("Baqso");

console.log(friends); //["Baqso", "Zizi", "Ioseb", "Maiko", "Karina"]

​

//REMOVE ELEMENTS

//POP - removes LAST ELEMENT FROM ARRAY

friends.pop(); //["Karina"]

//returns removed element

const popped = friends.pop();

console.log(popped); //["Karina"]

console.log(friends); //["Baqso", "Zizi", "Ioseb", "Maiko"]

​

//shift - Removes FIRST ELEMENT FROM THE ARRAY

friends.shift(); //["Baqso"]

console.log(friends); //["Zizi", "Ioseb", "Maiko"]

​

//indexOf - Tells the position of the element in the ARRAY

console.log(friends.indexOf("Zizi")); //0

//if we write the element which is not in the ARRAY we get : -1

console.log(friends.indexOf("zizi")); //-1, we need to write in CamelCase

​

//includes - modern method of indexOf

//includes - testing with STRICT EQUALITY

console.log(friends.includes("Zizi")); //true

​

​

​

let dailyActivities = ['sleep', 'work', 'exercise']

let newRoutine = ['eat'];

​

// sorting elements in the alphabetical order

dailyActivities.sort();

console.log(dailyActivities); // ['exercise', 'sleep', 'work']

​

//finding the index position of string

const position = dailyActivities.indexOf('work');

console.log(position); // 2

​

// slicing the array elements

const newDailyActivities = dailyActivities.slice(1);

console.log(newDailyActivities); // [ 'sleep', 'work']

​

// concatenating two arrays

const routine = dailyActivities.concat(newRoutine);

console.log(routine); // ["exercise", "sleep", "work", "eat"]