js-utilifns

js-utilifns

A collection of JavaScript utility functions for common operations on dates, numbers, objects, arrays and strings. This library was built to improve my developer's knowledge of JavaScript while creating a useful set of tools for personal projects and, potentially, for others in the community. js-utilifns aims to provide a consistent and reliable set of functions, reducing the need for repetitive coding.

Features

• Functions for manipulating arrays, dates, numbers, objects, and strings.
• Each function includes error handling and input validation for increased reliability.
• Simple and easy-to-use API with clear JSDoc documentation.
• ES6 module-based structure for easy imports in modern JavaScript projects.
• Comprehensive unit tests using Jest.

Installation

You can install js-utilifns using npm or yarn:

npm install js-utilifns

If using yarn:

yarn add js-utilifns

Documentation (JSDoc)

You can View documentation here

Usage

You can import individual utility functions as needed:

Example: Using getDayOfTheWeek() from dateUtils.js

import { getDayOfTheWeek } from ".js-utilifns";

console.log(getDayOfTheWeek(new Date("2025-03-26"))); // Outputs: "Wednesday"
console.log(getDayOfTheWeek(new Date("2020,10,01"))); // Outputs: "Thursday"

Example: Using getRandomInt() from numberUtils.js

import { getRandomInt } from "js-utilifns";

console.log(getRandomInt(1, 10)); // Outputs a random integer between 1 and 10

Example: Using hasKey() from objectUtils.js

import { hasKey } from "js-utilifns";

const newObject = {name: "John Doe", age: 42};
console.log(hasKey(newObject, "name")); // Outputs: true

Available Utility Functions

Date Utilities (dateUtils.js)

Function	Description
getDayOfTheWeek(date)	Returns the day of the week (e.g., "Monday").
diffInDays(date1, date2)	Calculates the number of days between two dates.
diffInMonths(date1, date2)	Calculates the number of months between two dates.
diffInYears(date1, date2)	Calculates the number of years between two dates.
isLeapYear(year)	Checks if a given year is a leap year.

Number Utilities (numberUtils.js)

Function	Description
isEven(number)	Checks if a number is even. Returns true if even, false if odd, and undefined if input is invalid.
isOdd(number)	Checks if a number is odd. Returns true if odd, false if even, and undefined if input is invalid.
roundTo(number, decimalPlaces)	Rounds a number to a specified decimal place. Returns NaN if input is invalid.
getRandomInt(min, max)	Generates a random integer within a specified range (inclusive). Returns NaN if inputs are invalid.
sum(numbersArray)	Returns the sum of all numbers in an array. Returns NaN if input is not a valid array or contains non-numeric values.

Object Utilities (objectUtils.js)

Function	Description
isEmpty(obj)	Checks if an object is empty (has no enumerable properties). Returns true if empty, false otherwise.
merge(target, source)	Merges two objects, with properties from the second object overwriting those in the first.
deepClone(obj)	Creates a deep clone of an object. Returns a new object with the same properties.
hasKey(obj, key)	Checks if an object has a specific property as its own (not inherited). Returns true if property exists, false otherwise.
get(obj, path, defaultValue)	Retrieves the value at a given path within an object. Returns the value at the specified path or the default value.
set(obj, path, value)	Sets the value at a given path within an object. Returns the updated object.

String Utilities (stringUtils.js)

Function	Description
capitalize(str)	Capitalizes the first letter of a string. Returns the capitalized string or an empty string if input is invalid.
camelCase(str)	Converts a string to camelCase. Returns the camelCased string.
kebabCase(str)	Converts a string to kebab-case. Returns the kebab-cased string.
snakeCase(str)	Converts a string to snake_case. Returns the snake_cased string.
truncate(str, length)	Truncates a string to a specified length, adding "..." if truncated. Returns the truncated string.
reverseString(str)	Reverses a string. Returns the reversed string.
countOccurrences(str, sub)	Counts the occurrences of a substring within a string. Returns the number of occurrences.
startsWith(str, prefix)	Checks if a string starts with a given substring. Returns true if it starts with the prefix, false otherwise.
endsWith(str, suffix)	Checks if a string ends with a given substring. Returns true if it ends with the suffix, false otherwise.
removeWhitespace(str)	Removes all whitespace from a string. Returns the string without whitespace.

Array Utilities (arrayUtils.js)

Function	Description
isArrayEmpty(arr)	Checks if an array is empty .
isArrayEqual(arr1, arr2)	Performs a shallow comparison to check if two arrays are equal in both value and order.
chunkArray(array, size)	Splits an array into smaller arrays ("chunks") of a specified size.
removeDuplicates(array)	Removes duplicate primitive values from an array
removeFalsy(array)	Remove falsy values from an array
difference(arr1, arr2)	Returns the elements in the first array that are not present in the second array. Case-sensitive comparison.
intersection(arr1, arr2)	Returns common elements between two arrays. Case-sensitive comparison.
hasDuplicates(array)	Checks if an array contains duplicate values

Running Tests

This library is thoroughly tested using Jest. You can run the tests locally by running:

npm test

License

This project is licensed under the MIT License. You are free to use, modify, and distribute it.

Contributing

Want to contribute? Follow these steps:

• Fork the repository.
• Create a new branch (feature-xyz).
• Make your changes and commit them.
• Push to your forked repo.
• Open a Pull Request .

Contact

Author: Tiago Costa Rebelo

Have suggestions or found a bug? Open an issue or reach out!

Support the Project

Star this repo if you found it useful!