check-toolkit

A lightweight TypeScript utility library focused on type guards and small, tree-shakeable helpers. Zero runtime dependencies — import only what you need.

Why check-toolkit?

• Lightweight — small implementations without heavy lodash-style utilities
• Tree-shakeable — each function is imported separately
• Zero runtime dependencies — nothing extra in your bundle
• Typed — type guards like isNotNil and isPlainObject narrow types in TypeScript

Installation

npm install check-toolkit

Usage

import { isString, isPlainObject, pick } from "check-toolkit";

console.log(isString("test")); // true
console.log(isPlainObject({ a: 1 })); // true

const payload = pick({ a: 1, b: 2, c: 3 }, ["a", "c"]);
// { a: 1, c: 3 }

Available Functions

Type Checking

• isSymbol - Check if value is a symbol
• isArray - Check if value is an array
• isArrayLike - Check if value is array-like
• isNan - Check if value is NaN
• isObject - Check if value is an object
• isNull - Check if value is null
• isFunction - Check if value is a function
• isNumber - Check if value is a number
• isString - Check if value is a string
• isBoolean - Check if value is a boolean
• isPlainObject - Check if value is a plain object
• isUndefined - Check if value is undefined
• isNotUndefined - Check if value is not undefined
• isNil - Check if value is null or undefined
• isNotNil - Check if value is not null and not undefined
• isNotNaN - Check if value is not NaN
• isEmpty - Check if value is empty
• isEqual - Check if two values are equal
• isMatch - Check if object matches source

Object Operations

• pick - Creates a new object with only the specified keys
• omit - Creates a new object without the specified keys
• pickBy - Creates a new object with entries that satisfy a predicate
• omitBy - Creates a new object without entries that satisfy a predicate

Array Operations

• compact - Removes falsy values from an array
• countBy - Counts elements grouped by iteratee result
• uniq - Creates an array with unique values
• uniqBy - Like uniq but accepts an iteratee
• groupBy - Groups array elements by iteratee result
• partition - Splits an array into two groups by predicate
• sortBy - Creates a sorted copy by iteratee result
• difference - Create an array of unique values not included in other arrays
• differenceBy - Like difference but accepts iteratee
• differenceWith - Like difference but accepts comparator
• keyBy - Creates an object composed of keys generated from array

String Operations

• capitalize - Uppercases the first character only (not title case; uses toUpperCase)
• camelCase - Converts a string to camel case
• kebabCase - Converts a string to kebab case
• snakeCase - Converts a string to snake case
• startCase - Converts each word to start case (title-style)
• escape - Escapes HTML special characters
• unescape - Unescapes HTML special characters
• escapeRegExp - Escapes RegExp special characters

Clone Operations

• clone - Creates a shallow clone of a value
• cloneDeep - Creates a deep clone of a value
• cloneWith - Creates a shallow clone with a customizer
• cloneDeepWith - Creates a deep clone with a customizer

Function Utilities

• debounce - Creates a debounced function
• throttle - Creates a throttled function
• noop - No-op default callback
• identity - Returns the first argument unchanged
• once - Invokes a function at most once

Math

• clamp - Clamps a number between min and max

Promise

• delay - Resolves after the specified milliseconds

Testing

To run the test suite:

npm run test

To build the project:

npm run build

To start development server:

npm run dev

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT License

Originally created by Volodymyr Cherevchuk