Chapter 1: Introduction

Recently, I came across some intriguing articles about one-liners in JavaScript. Inspired by them, I decided to compile a collection to share with you. I trust this will prove beneficial in your coding endeavors. Although some of these methods may lack elegance, the primary goal of this article is to enhance your skills with various APIs.

Chapter 2: Date Operations

1. Validating a Date

   This one-liner checks if a provided date is valid.

const isDateValid = (...val) => !Number.isNaN(new Date(...val).valueOf());

isDateValid("December 27, 2022 13:14:00"); // true

2. Calculating Date Intervals

   Use this to find the difference between two dates.

const dayDif = (date1, date2) => Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000);

dayDif(new Date("2022-08-27"), new Date("2022-12-25")); // 120

120 days until Christmas.

3. Finding the Day of the Year

   This method reveals which day of the year a specific date falls on.

const dayOfYear = (date) => Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);

dayOfYear(new Date()); // 239

239 days have passed in 2022.

4. Time Formatting

   Convert a date into an hh:mm:ss format.

const timeFromDate = date => date.toTimeString().slice(0, 8);

timeFromDate(new Date(2021, 11, 2, 12, 30, 0)); // 12:30:00

For the current time:

timeFromDate(new Date()); // now time 09:00:00

Chapter 3: String Manipulation

1. Capitalizing the First Letter

   This method capitalizes the first character of a string.

const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1);

capitalize("hello world"); // Hello world

2. Reversing a String

   Use this to reverse a given string.

const reverse = str => str.split('').reverse().join('');

reverse('hello world'); // 'dlrow olleh'

3. Generating a Random String

   This method creates a random string.

const randomString = () => Math.random().toString(36).slice(2);

randomString();

4. String Truncation

   Truncate a string to a specified length.

const truncateString = (string, length) => string.length < length ? string : ${string.slice(0, length - 3)}...;

truncateString('Hi, I should be truncated because I am too loooong!', 36); // 'Hi, I should be truncated because...'

5. Removing HTML from a String

   This method strips HTML tags from a string.

const stripHtml = html => (new DOMParser().parseFromString(html, 'text/html')).body.textContent || '';

Chapter 4: Array Processing

1. Removing Duplicates

   This method eliminates duplicate items from an array.

const removeDuplicates = (arr) => [...new Set(arr)];

console.log(removeDuplicates([1, 2, 2, 3, 3, 4, 4, 5, 5, 6]));

2. Checking Array Emptiness

   Determine if an array is empty.

const isNotEmpty = arr => Array.isArray(arr) && arr.length > 0;

isNotEmpty([1, 2, 3]); // true

3. Merging Arrays

   Combine two arrays using the following methods.

const merge = (a, b) => a.concat(b);

const merge = (a, b) => [...a, ...b];

Chapter 5: Numerical Operations

1. Odd or Even Check

   This method determines if a number is odd or even.

const isEven = num => num % 2 === 0;

isEven(996);

2. Calculating the Average

   Get the average of a set of numbers.

const average = (...args) => args.reduce((a, b) => a + b) / args.length;

average(1, 2, 3, 4, 5); // 3

3. Generating a Random Integer

   This method retrieves a random integer between two numbers.

const random = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);

random(1, 50);

4. Rounding to Specific Digits

   Round a number to a certain number of decimal places.

const round = (n, d) => Number(Math.round(n + "e" + d) + "e-" + d);

round(1.005, 2); // 1.01

round(1.555, 2); // 1.56

Chapter 6: Color Manipulation

1. RGB to Hex Conversion

   Convert RGB values to hexadecimal format.

const rgbToHex = (r, g, b) => "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);

rgbToHex(255, 255, 255); // '#ffffff'

2. Random Hexadecimal Color

   Generate a random hexadecimal color value.

const randomHex = () => #${Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, "0")};

randomHex();

Chapter 7: Browser Operations

1. Copying Text to Clipboard

   Copy text to the clipboard using this method.

const copyToClipboard = (text) => navigator.clipboard.writeText(text);

copyToClipboard("Hello World");

2. Clearing Cookies

   Remove all cookies stored on the web page.

const clearCookies = document.cookie.split(';').forEach(cookie => document.cookie = cookie.replace(/^ +/, '').replace(/=.*/, =;expires=${new Date(0).toUTCString()};path=/));

3. Getting Selected Text

   Retrieve the text selected by the user.

const getSelectedText = () => window.getSelection().toString();

getSelectedText();

4. Checking Dark Mode

   Determine if the current environment is using dark mode.

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;

console.log(isDarkMode);

5. Navigating to the Top of the Page

   Return to the top of the page.

const goToTop = () => window.scrollTo(0, 0);

goToTop();

6. Tab Activity Check

   Check if the current tab is active.

const isTabInView = () => !document.hidden;

7. Apple Device Detection

   Determine if the current device is an Apple device.

const isAppleDevice = () => /Mac|iPod|iPhone|iPad/.test(navigator.platform);

isAppleDevice();

8. Scroll Detection

   Check if the page is scrolled to the bottom.

const scrolledToBottom = () => document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight;

9. URL Redirection

   Redirect to a specified URL.

const redirect = url => location.href = url;

10. Opening Print Dialog

    Open the browser's print dialog.

const showPrintDialog = () => window.print();

Chapter 8: Additional Utilities

1. Random Boolean Value

   Generate a random Boolean value.

const randomBoolean = () => Math.random() >= 0.5;

randomBoolean();

2. Variable Swapping

   Swap the values of two variables without a temporary variable.

[foo, bar] = [bar, foo];

3. Getting Variable Type

   Retrieve the type of a variable.

const trueTypeOf = (obj) => Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();

trueTypeOf(''); // string

trueTypeOf(0); // number

trueTypeOf(); // undefined

trueTypeOf(null); // null

trueTypeOf({}); // object

trueTypeOf([]); // array

trueTypeOf(0); // number

trueTypeOf(() => {}); // function

4. Temperature Conversion

   Convert between Celsius and Fahrenheit.

const celsiusToFahrenheit = (celsius) => celsius * 9/5 + 32;

const fahrenheitToCelsius = (fahrenheit) => (fahrenheit - 32) * 5/9;

celsiusToFahrenheit(15); // 59

celsiusToFahrenheit(0); // 32

celsiusToFahrenheit(-20); // -4

fahrenheitToCelsius(59); // 15

fahrenheitToCelsius(32); // 0

5. Checking Object Emptiness

   Verify if a JavaScript object is empty.

const isEmpty = obj => Reflect.ownKeys(obj).length === 0 && obj.constructor === Object;

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