5 JavaScript Useful Functions

5 JavaScript Useful Functions
December 12, 2023

1. Function to Format Number as Currency

function formatCurrency(number) {
  return new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(number);

This code defines a function named formatCurrency which is used to format a number into a currency format, specifically in US dollars.

Function Name: formatCurrency:

Converts a number to US dollar format.

Parameter: number:

The number you want to convert.

Key Actions:

Uses Intl.NumberFormat to format the number.

Sets the format to US dollars ('en-US', { style: 'currency', currency: 'USD' }).

Returns the formatted number as a string, like "$100.00".

2. Function to Copy Text to Clipboard

function copyToClipboard(text) {
  const elem = document.createElement('textarea');
  elem.value = text;

Function Name: copyToClipboard

This function is used to copy text to the clipboard.

Parameter: text

The text you want to copy.

Creating a Text Area:

document.createElement('textarea'): Creates a new, hidden text area element on the webpage.

elem.value = text: Sets the value of this text area to the text you want to copy.

Adding to Document:

document.body.appendChild(elem): Temporarily adds the text area to the webpage so it can be used for copying.

Selecting the Text:

elem.select(): Selects (highlights) all the text in the text area.

Copying the Text:

document.execCommand('copy'): Copies the selected text to the clipboard, like pressing Ctrl+C.

Removing the Text Area:

document.body.removeChild(elem): Removes the text area from the webpage, as it's no longer needed.

3. Function to Get the Current URL

function getCurrentUrl() {
  return window.location.href;

Function Name: getCurrentUrl

It's a function designed to give you the current webpage's URL.

What it Does:

window.location.href: This part gets the full address (URL) of the webpage you are currently on.

Return Value:

The function returns the URL as a string of text.

4. Function to Scroll to the Top of the Page

function scrollToTop() {
  window.scrollTo(0, 0);

Function Name: scrollToTop

This function is designed to quickly take you to the very top of the webpage you're viewing.

What it Does:

window.scrollTo(0, 0): This command is the key part of the function.

It tells the browser to scroll to a specific position on the page.

The numbers (0, 0) represent the coordinates at the top-left corner of the webpage.


After this function runs, you'll find yourself at the top of the webpage, no matter where you were on that page before.

5. Function to Generate a UUID (Universally Unique Identifier)

function generateUUID() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random() * 16 | 0, v = c === 'x' ? r : (r & 0x3 | 0x8);
    return v.toString(16);

Function Name: generateUUID

It's designed to generate a unique string of characters, known as a UUID (Universally Unique Identifier).

UUID Format:

The UUID format is represented by the string 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.

This format includes random numbers and letters, separated by hyphens.

Generating Random Values:

.replace(/[xy]/g, function(c) { ... }): This part replaces each 'x' and 'y' in the format with random hexadecimal values (0-9 and a-f).

For each 'x', it uses a completely random value.

For 'y', it calculates a value that makes sure the UUID follows certain standards.

Random Number Calculation:

var r = Math.random() * 16 | 0: Generates a random number for each replacement.

v = c === 'x' ? r : (r & 0x3 | 0x8): Determines the final value to replace 'x' or 'y'.

Converting to Hexadecimal:

v.toString(16): Converts the value into a hexadecimal (base 16) number.

Return Value:

The function returns a unique string in the UUID format.

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