Arrays are used to store multiple values in a single variable.

Each value is called an element, and each element has a numeric position in the array, known as its index.

Arrays are zero-indexed, meaning the first element is at index 0, the second at index 1, and so on.

Arrays can contain any data type, including numbers, strings, and objects.

const arr1 = [2, 4, 6]; array

arr1[0]; element at index 0 → 2

arr1[1]; element at index 1 → 4

arr1[2]; element at index 2 → 6

arr1[3]; element at index 3 → undefined index not found

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Numbers are used to represent both integer and floating-point values.

Numbers are most commonly expressed in literal forms like 255 or 3.14159 ↴

let num1 = 5; → number

let num2 = 2.5; → number

let num3 = num1 + num2;

console.log(num3); returns ↴

7.5 → number

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Find the maximum difference between two numbers in an array using ↴

Math.max() static method → returns the largest of the numbers given as input parameters, or -Infinity if there are no parameters.

Math.min() static method → returns the smallest of the numbers given as input parameters, or Infinity if there are no parameters.

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spread syntax ... The spread operator allows an iterable (like an array) to be expanded in places where zero or more arguments are expected.

For example, it allows two or more arrays to be merged into one array.

const arr2 = [1, 2, 3, 4, 5];

const arr3 = [4, 5, 6, 7, 8];

const arr4 = [...arr2, ...arr3];

console.log(arr4); returns ↴

[1, 2, 3, 4, 5, 4, 5, 6, 7, 8]

The spread operator is useful when working with functions that do not accept an array as a single argument.

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Math.max() static method returns the largest of the numbers given as input parameters, or -Infinity if there are no parameters.

Directly pass numerical values as arguments.

Math.max(4, 2, 6, 5, 3); returns ↴

6

Use the spread syntax to pass an array of numbers.

const nums1 = [4, 2, 6, 5, 3];

Math.max(...nums1); returns ↴

6

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Math.min() static method returns the smallest of the numbers given as input parameters, or Infinity if there are no parameters.

Directly pass numerical values as arguments.

Math.min(4, 2, 6, 5, 3); returns ↴

2

Use the spread syntax to pass an array of numbers.

const nums2 = [4, 2, 6, 5, 3];

Math.min(...nums2); returns ↴

2

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Initialize a variable to hold the array find the maximum difference between two numbers.

const array1 = [4, 8, 6, 2, 5, 7, 9, 3]; → user input

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Define a function maxDifference to find the maximum difference between two numbers.

function maxDifference(arr) {}

The function takes an array as input arr and returns the maximum number between two numbers found in the array.

Return the difference between the maximum and minimum values.

return maxVal - minVal

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Find the maximum difference between two numbers in an array.

arr = [4, 8, 6, 2, 5, 7, 9, 3]

maxVal = Math.max(...arr) → 9

minVal = Math.min(...arr) → 2

maxVal - minVal → 9 - 2

7 → maximum difference between two numbers in array

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Call the function with ↴

maxDifference(array1);

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Find the maximum difference between two numbers in an array.