09_arrays_methods.js

//15. forEach() - execute a function for every element
number.forEach((n) => {
    console.log("Number :", n);
});


//16. includes() - check whether an element exists
console.log("Is 4 present?", number.includes(4));
console.log("Is 10 present?", number.includes(10));


//17. indexOf() - find the first index of an element
console.log("Index of 3 :", number.indexOf(3));


//18. lastIndexOf() - find the last index of an element
let nums = [1, 2, 3, 2, 4, 2];

console.log("Last index of 2 :", nums.lastIndexOf(2));


//19. findLast() - find the last element satisfying a condition
let lastEven = number.findLast(n => n % 2 === 0);

console.log("Last even number :", lastEven);


//20. findLastIndex() - find the index of the last matching element
let lastEvenIndex = number.findLastIndex(n => n % 2 === 0);

console.log("Last even index :", lastEvenIndex);


//21. flatMap() - map + flat together
let values = [1, 2, 3];

let result = values.flatMap(n => [n, n * 2]);

console.log("flatMap :", result);
// [1, 2, 2, 4, 3, 6]


//22. Array.from() - create an array from an iterable/string
let word = "HELLO";

let letters = Array.from(word);

console.log("Array from string :", letters);


//23. Array.of() - create an array from given values
let data = Array.of(10, 20, 30, 40);

console.log("Array.of :", data);


//24. fill() - replace elements with a value
let fillArray = [1, 2, 3, 4, 5];

fillArray.fill(0, 1, 4);

console.log("After fill :", fillArray);
// [1, 0, 0, 0, 5]


//25. copyWithin() - copy part of an array to another position
let copyArray = [1, 2, 3, 4, 5];

copyArray.copyWithin(0, 3);

console.log("After copyWithin :", copyArray);
// [4, 5, 3, 4, 5]


//26. toSorted() - sort without changing original array
let original = [5, 2, 8, 1];

let sorted = original.toSorted((a, b) => a - b);

console.log("Original :", original);
console.log("Sorted :", sorted);


//27. toReversed() - reverse without changing original array
let original2 = [1, 2, 3, 4];

let reversed = original2.toReversed();

console.log("Original :", original2);
console.log("Reversed :", reversed);


//28. toSpliced() - splice without changing original array
let original3 = [1, 2, 3, 4, 5];

let newArray = original3.toSpliced(2, 1, 99);

console.log("Original :", original3);
console.log("New array :", newArray);


//29. at() - access element using positive or negative index
let colors = ["red", "green", "blue", "yellow"];

console.log("First :", colors.at(0));
console.log("Last :", colors.at(-1));


//30. entries() - get index and value together
let fruits2 = ["mango", "apple", "banana"];

for (let [index, value] of fruits2.entries()) {
    console.log(index, value);
}


//31. keys() - get array indexes
for (let index of fruits2.keys()) {
    console.log("Index :", index);
}


//32. values() - get array values
for (let value of fruits2.values()) {
    console.log("Value :", value);
}