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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Destructuring

The destructuring syntax is a JavaScript syntax that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.

const arr2 = ["Hello", "World"]; → array

const [a, b] = arr2;

console.log(a); returns ↴

"Hello" → first element in array

console.log(b); returns ↴

"World" → second element in array

Array destructuring assigns the first and second elements of the array directly to a and b, respectively. This eliminates the need for additional indexing, making the code cleaner and more intuitive.

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Temperature conversion formulas

Fahrenheit to Celsius ↴

Celsius = (Fahrenheit - 32) × 5 ⁄ 9

Fahrenheit to Kelvin ↴

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Initialize a variable to hold the number representing the temperature in Fahrenheit.

const tempF = 212; → user input

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Define a function convertTempF to convert temperature.

function convertTempF(degF) {}

The function takes a number as input degF and using the conversion formulas, converts it to Celsius and Kelvin.

Convert degF to Celsius and using formula ...

const degC = (degF - 32) * 5 / 9 degC

Convert degF to Kelvin using formula ...

Use destructuring to assign the returned values directly to degC and degK variables.

Call the function and destructure the results.

degC returns → 100 Celcius value

degK returns → 373.15 Kelvin value

The results from the function may then be manipulated, for example, to display results to 2 decimal places.

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Call the function with ↴

convertTempF(tempF);

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Convert Fahrenheit to Celsius & Kelvin.

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Alternative - create an array to hold the converted temperatures ↴

Convert Fahrenheit to Celsius & Kelvin.