kr-corekit

A comprehensive collection of TypeScript utility functions for modern web development.

Features

- 🛠️ Comprehensive: String, object, cookie, number, validation, format, search query, device, type, storage and common utilities
- 📦 Tree-shakable: Import only what you need
- 🔒 Type-safe: Full TypeScript support with type definitions
- ⚡ Lightweight: Minimal dependencies and optimized for performance
- 🧪 Well-tested: Extensive test coverage with comprehensive test cases

Installation

``bash
npm install kr-corekit


or

pnpm add kr-corekit

or

yarn add kr-corekit
`

Usage

$3

`typescript
import {
stringUtil,
objectUtil,
cookieUtil,
numberUtil,
validationUtil,
commonUtil,
formatUtil,
searchQueryUtil,
typeUtil,
deviceUtil,
} from "kr-corekit";

// String utilities
const escaped = stringUtil.escapeHtml("

");
const unescaped = stringUtil.unescapeHtml("<div>Hello</div>");
const slug = stringUtil.slugify("Hello World! 안녕하세요"); // "hello-world-안녕하세요"

// Object utilities
const cleaned = objectUtil.clearNullProperties({ a: 1, b: null, c: 3 });
const frozen = objectUtil.deepFreeze({ a: { b: 1 } });
const withoutKey = objectUtil.removeKey("b", { a: 1, b: 2, c: 3 }); // { a: 1, c: 3 }

// Number utilities
const total = numberUtil.sum(1, 2, 3, 4, 5); // 15
const difference = numberUtil.subtract(10, 3); // 7
const product = numberUtil.multiply(2, 3, 4); // 24

// Validation utilities
const isValid = validationUtil.checkEmail("user@example.com"); // true
const isHttpUrl = validationUtil.checkHttpUrl("https://example.com"); // true
const isDomain = validationUtil.checkDomain("example.com"); // true
const isBase64 = validationUtil.checkBase64("U29tZSB2YWxpZCBiYXNlNjQgc3RyaW5n"); // true
const isPasswordValid = validationUtil.checkPassword("Abc123!@#", {
minLength: 8,
requireUppercase: true,
requireLowercase: true,
requireNumber: true,
requireSpecialChar: true,
}); // true

// Common utilities
const empty = commonUtil.isEmpty(""); // true
const notEmpty = commonUtil.isEmpty("hello"); // false
const nullCheck = commonUtil.isNull(null); // true
const notNull = commonUtil.isNull("hello"); // false
await commonUtil.sleep(1000); // Pauses execution for 1 second
const copied = await commonUtil.copyToClipboard("Hello, World!"); // true if successful
const encoded = commonUtil.encodeBase64("Hello 한글!"); // Base64 encoded string
const decoded = commonUtil.decodeBase64(encoded); // "Hello 한글!"
const debouncedFn = commonUtil.debounce(() => console.log("Called!"), 300); // Debounced function
const throttledFn = commonUtil.throttle(() => console.log("Throttled!"), 300); // Throttled function

// Storage
commonUtil.storage.set("user", { id: 1, name: "John" }); // Stores object in localStorage
const user = commonUtil.storage.get<{ id: number; name: string }>("user"); // Retrieves typed object
commonUtil.storage.remove("user"); // Removes item from localStorage

// Retry utilities
const result = await commonUtil.retry(async () => {
const response = await fetch("/api/data");
if (!response.ok) throw new Error("API failed");
return response.json();
}, 3); // Retry up to 3 times

// More retry examples
const userData = await commonUtil.retry(async () => {
return await fetchUserData();
}); // Uses default 3 retries

const fileUpload = await commonUtil.retry(async () => {
return await uploadFile(file);
}, 5); // Custom retry count

// Search Query utilities
const queryParams = searchQueryUtil.getAllQuery(); // { key: ["value1", "value2"], id: "123" }

// Type utilities
const isPlain = typeUtil.isPlainObject({}); // true
const isNotPlain = typeUtil.isPlainObject(new Date()); // false

// Device utilities
const device = deviceUtil.getDevice(); // { isMobile: false, isTablet: false, isDesktop: true, isIOS: false, isAndroid: false }

// Cookie utilities
cookieUtil.setCookie("theme", "dark");
const theme = cookieUtil.getCookie("theme");
// Format utilities
const formattedPhone = formatUtil.formatPhoneNumber("01012345678"); // "010-1234-5678"
`

$3

For optimal bundle size, import only the functions you need:

`typescript
// Option 1: Import specific functions (best tree-shaking)
import { escapeHtml, unescapeHtml } from "kr-corekit";
import { sum, multiply } from "kr-corekit";
import { clearNullProperties, deepFreeze } from "kr-corekit";

// Option 2: Import from specific utility modules (good tree-shaking)
import { escapeHtml } from "kr-corekit/stringUtil";
import { sum } from "kr-corekit/numberUtil";
import { clearNullProperties } from "kr-corekit/objectUtil";
import { storage } from "kr-corekit/commonUtil";

// Usage remains the same
const escaped = escapeHtml("

");
const total = sum(1, 2, 3, 4, 5);
const cleaned = clearNullProperties({ a: 1, b: null, c: 3 });
storage.set("data", { key: "value" });
`

$3

- Full import: ~8.3KB (2.9KB gzipped)
- Tree-shaken import: Only includes functions you use
- Individual module import: Further optimized for specific utilities

API Reference

$3

- escapeHtml(str: string): string - Escapes HTML special characters
- unescapeHtml(str: string): string - Unescapes HTML entities
- slugify(text: string): string - Converts a string to URL-friendly slug format. Replaces spaces with hyphens, removes special characters, converts to lowercase, and supports Korean characters (e.g., "Hello World! 안녕" → "hello-world-안녕")

$3

- clearNullProperties(obj: object): object - Removes null/undefined properties
- deepFreeze(obj: object): object - Deep freezes an object recursively
- removeKey(key: string, obj: Record): object - Returns a new object with the specified key removed

$3

- sum(...numbers: number[]): number - Calculates sum of numbers
- subtract(...numbers: number[]): number - Calculates subtraction of numbers
- multiply(...numbers: number[]): number - Calculates multiplication of numbers

$3

- formatPhoneNumber(phone: string): string - Formats a phone number string to a standard format (e.g., "010-1234-5678")
- formatNumberWithCommas(value: number | string | null | undefined): string - Converts numbers or strings to comma-separated format (e.g., "1,234,567"). Returns empty string for null/undefined values.

$3

- checkEmail(email: string): boolean - Validates email format
- checkHttpUrl(url: string): boolean - Validates HTTP/HTTPS URL format
- checkDomain(domain: string): boolean - Validates domain name format
- checkBase64(value: string): boolean - Validates whether a string is a valid base64 encoded value
- checkPassword(password: string, options?: { minLength?: number; maxLength?: number; requireUppercase?: boolean; requireLowercase?: boolean; requireNumber?: boolean; requireSpecialChar?: boolean }): boolean - Validates password strength and requirements

$3

- set(key: string, value: T): void - Stores a value in localStorage with automatic JSON serialization. Supports objects, arrays, and primitive types. Safe for SSR environments.
- get(key: string): T | null - Retrieves a value from localStorage with automatic JSON parsing. Returns null if key doesn't exist or parsing fails. Type-safe with generic support.
- remove(key: string): void - Removes a specific item from localStorage. Safe for SSR environments.

Features:

- 🔒 SSR Safe: All methods handle server-side rendering environments gracefully
- 📦 Type Safe: Full TypeScript support with generics
- 🛡️ Error Handling: Comprehensive error handling with automatic cleanup of corrupted data
- 🔄 Auto Serialization: Automatic JSON serialization/deserialization for complex data types

$3

- isEmpty(value: unknown): boolean - Checks if a value is empty (null, undefined, "", 0, [], {}, empty Set/Map, NaN, or invalid Date)
- isNull(value: unknown): value is null - Type guard that checks if a value is null and narrows the type
- sleep(ms: number): Promise - Pauses execution for a specified number of milliseconds
- copyToClipboard(text: string): Promise - Copies text to the user's clipboard. Uses modern Clipboard API with fallback to legacy execCommand method. Returns true if successful, false if failed.
- encodeBase64(str: string, options?: { convertSpecialChars?: boolean }): string - Encodes a string to Base64 format with optional special character handling
- decodeBase64(str: string, options?: { convertSpecialChars?: boolean }): string - Decodes a Base64 string back to original text with optional special character handling
- debounce(fn: T, delay?: number): (...args: Parameters) => void - Creates a debounced function that delays execution until after a specified delay (default 300ms) has passed since its last invocation
- throttle(fn: T, limit?: number): (...args: Parameters) => void - Creates a throttled function that only executes at most once per specified time interval (default 300ms), ignoring subsequent calls within the limit
- storage.set(key: string, value: T): void - Stores a value in localStorage with automatic JSON serialization. Supports objects, arrays, and primitive types. Safe for SSR environments.
- storage.get(key: string): T | null - Retrieves a value from localStorage with automatic JSON parsing. Returns null if key doesn't exist or parsing fails. Type-safe with generic support.
- storage.remove(key: string): void - Removes a specific item from localStorage. Safe for SSR environments.

Storage Features:

- 🔒 SSR Safe: All methods handle server-side rendering environments gracefully
- 📦 Type Safe: Full TypeScript support with generics
- 🛡️ Error Handling: Comprehensive error handling with automatic cleanup of corrupted data
- 🔄 Auto Serialization: Automatic JSON serialization/deserialization for complex data types

$3

- retry(fn: () => Promise, loop?: number): Promise - Retries an asynchronous function up to the specified number of times (default 3) if it fails. Automatically re-attempts on error and returns the result of the first successful execution, or throws the last error if all retries fail.

$3

- getAllQuery(): Record - Parses the current URL's query string and returns an object with key-value pairs. Values appear as arrays when the same key is used multiple times.

$3

- isPlainObject(value: unknown): boolean - Checks if a value is a plain object (created by Object literal or Object.create(null)), excluding arrays, dates, and other built-in objects.

$3

- getDevice(): DeviceInfo - Detects the user's device environment. Returns information about device type (mobile/tablet/desktop) and operating system (iOS/Android). Uses navigator.userAgent for detection and provides safe fallback for SSR environments.

$3

- setCookie(name: string, value: string, options?: object): void - Sets a cookie
- getCookie(name: string): string | null` - Gets a cookie value

Contributing

Contributions are welcome! Please read our contributing guidelines and submit pull requests to our repository.

License

MIT License - see LICENSE file for details.