In this post, we will look at some of the most common tasks that developers do and see how we can do them without using any libraries or frameworks.

Clone an object

const obj = { a: 1, b: 2 };
const clone = obj.structuralClone();

const url = new URL(window.location.href);

Remove multiple line breaks

const text = `Hello

World`;
const cleanText = text.replace(/\n{2,}/g, "\n");

Remove array duplicates

const arr = [1, 2, 3, 3, 4, 5, 5, 6];
const uniqueArr = [...new Set(arr)];

Generate a random number between two numbers

const min = 1;
const max = 10;
const random = Math.floor(Math.random() * (max - min + 1)) + min;

Shuffle an array

const arr = [1, 2, 3, 4, 5];
const shuffledArr = arr.sort(() => Math.random() - 0.5);

Detect Dark Mode

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

Generate a random color

const generateRandomHexColor = () =>
  `#${Math.floor(Math.random() * 0xffffff).toString(16)}`;

Sort an array of objects by a property

const arr = [
  { name: "Adem", age: 26 },
  { name: "Jane", age: 25 },
  { name: "Bob", age: 20 },
];
// Sort by age
const sortedArr = arr.sort((a, b) => a.age - b.age);

Get the intersection of arrays

const arr1 = [1, 2, 3, 4, 5];
const arr2 = [3, 4, 5, 6, 7];
const intersection = (a, ...arr) =>
  [...new Set(a)].filter((v) => arr.every((b) => b.includes(v)));

intersection(arr1, arr2); // [3, 4, 5]

Get the number of days in a month

const getDaysInMonth = (month, year) => new Date(year, month, 0).getDate();

daysInMonth(2, 2024);
// 29

Flatten an array

const flatten = (arr) =>
  arr.reduce(
    (a, b) => (Array.isArray(b) ? [...a, ...flatten(b)] : [...a, b]),
    []
  );
flatten([
  [1, 2],
  [3, 4],
  [5, 6],
]);
// [1, 2, 3, 4, 5, 6]

Check if two objects are equal

const isEqual = (a, b) => JSON.stringify(a) === JSON.stringify(b);
isEqual({ name: "Adem", age: 26 }, { name: "Adem", age: 26 });
// true

Slugify a string

const slugify = (str) =>
  str
    .toLowerCase()
    .replace(/[^\w ]+/g, "")
    .replace(/ +/g, "-");

slugify("Hello World");
// hello-world

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