//ARRAY METHODS

//1 . push() -Adds element to the end of an array.

// -Returns new length of an array

let arrNums = [1, 2, 3, 4]

arrNums.push(5)

console.log(arrNums)//[1,2,3,4,5]

//2. pop() -removes the last element from an array.

// -Returns the removed element

let cars = ["BWM", "Mercedes-Benz", "Toyota-Vitz", "Subaru"]

cars.pop()

console.log(cars)//['BWM','Mercedes-Benz','Toyota-Vitz']

//3. shift() -Removes the first element from an array.

let fruits1 = ["apple", "banana", "orange"];

let first = fruits1.shift();

console.log(first); // "apple"

console.log(fruits1); // ["banana", "orange"]

//4. unshift() -Adds one or more elements at the beginnig of an array.

// -Returns the new length of an array.

let alphabets = ['A', 'B', 'C', 'D']

alphabets.unshift('Z', 'Y')

console.log(alphabets)//[ 'Z', 'Y', 'A', 'B', 'C', 'D' ]

//5. map()-Creates a new array by applying a function to each element.

let nums1 = [1, 2, 3, 4, 5]

let productOfNums = nums1.map(elm => elm * 2)//multiply each element in an array by 2

console.log(productOfNums)//[2,4,6,8,10]

//6. filter()-Creates a new array with elements that passes a particular test or passes a condition

let listOne = [2, 3, 4, 5, 10, 12, 13]

let listTwo = listOne.filter(nums => nums % 2 == 0)//filters even numbers

console.log(listTwo)//[2,4,10,12]

//7. reduce()- Reduces an array to single value by applying a fuction

let demoOne = [2, 3, 4, 5]

let demoSum = demoOne.reduce((x, y) => x + y)

console.log(demoSum)// 2+3+4+5 =14

//8. forEach()-Executes a fuction for each array element

let animals = ["Dog", "Rabbit", "Cow", "Pig"]

let animalIndex = animals.forEach((animals, index) => {

console.log(index + ":" + animals)

// 0: Dog

// 1: Rabbit

// 2: Cow

// 3: Pig

})

//9.find()-Returns the first element that passes a condition

// -If nothing matches ,returns undefined

let el = [1, 2, 3, 4, 5, 6]

let found = el.find((e) => e > 3)

console.log(found)//4

//10.concat()-Joins two or more arrays without changing the original

let origin = [1, 2, 3, 4]

let original2 = [5, 6, 7, 8]

let finalArr = origin.concat(original2)

console.log(finalArr)//[1,2,3,4,5,6,7,8]

//11.join()-Joins array elements into a sting with a separator

let words = ["Hello", "World"];

console.log(words.join(" ")); // "Hello World"

console.log(words.join("-")); // "Hello-World"

//12.splice()-Adds/removes items in the origianal array

//format - array.splice(start,deletecount,newItems...)

let fruits2 = ["apple", "banana", "cherry"];

fruits2.splice(1, 1, "mango");

console.log(fruits2); // ["apple", "mango", "cherry"]

//13.slice()-Returns a portion of the array ,does not change the original

let arr = [1, 2, 3, 4, 5];

console.log(arr.slice(1, 4)); // [2, 3, 4]

console.log(arr); // [1, 2, 3, 4, 5]

//14.indexOf()-Returns the index of the first occurrence of the value

// -Returns -1 if not found.

let items = ["pen", "book", "pen"];

console.log(items.indexOf("pen")); // 0

console.log(items.indexOf("laptop")); // -1

//15.flat()-Flattens nested arrays.

let nested = [1, [2, [3, 4]]];

console.log(nested.flat()); // [1, 2, [3, 4]]

console.log(nested.flat(2)); // [1, 2, 3, 4]

//16.some()-Returns true if at least one element passes a condition.

let nums2 = [1, 3, 5, 8];

console.log(nums2.some(n => n % 2 === 0)); // true (because 8 is even)

//17.every()Returns true if all element passes a condition

let nums3 = [2, 4, 6];

console.log(nums3.every(n => n % 2 === 0)); // true

//18.sort()-Sorts elements as strings by default.

// -To sort numbers correctly, pass a compare function.

let letters = ["c", "a", "b"];

console.log(letters.sort()); // ["a", "b", "c"]

let nums4 = [40, 5, 100, 25];

console.log(nums4.sort()); // [100, 25, 40, 5] (wrong for numbers)

console.log(nums4.sort((a, b) => a - b)); // [5, 25, 40, 100] (correct)

//19.reverse()-Reverses the order of elements in an array.

let nums5 = [9,6];

console.log(nums5.reverse()); // [6, 9]

//20.fill()-Fills all the elements in an array with a static value.

let nums6 = [];

console.log(nums6.fill(0, 0, 5)); // [0, 0, 0, 0, 0]

//21.includes()-Checks if an array contains a specific element.

let nums7 = [1, 2, 3, 4, 5];

console.log(nums7.includes(3)); // true