Core Type Matching Function

const typeString = Object.prototype.toString;
export function matchesType(input: unknown, expectedType: string): boolean {
    return typeString.call(input) === `[object ${expectedType}]`;
}

Check if Defined

export function isDefined<T = unknown>(value?: T): value is T {
    return typeof value !== 'undefined';
}

export function isUndefined<T = unknown>(value: T): value is T {
    return !isDefined(value);
}

Check if String

export function isString(input: unknown): input is string {
    return matchesType(input, 'String');
}

Check if Object

export function isObjectLike(input: any): input is Record<any, any> {
    return input !== null && matchesType(input, 'Object');
}

Check if Array

export function isArray(input: any): input is any[] {
    return Array.isArray(input);
}

Check if Map

export function isMap(input: unknown): input is Map<any, any> {
    return matchesType(input, 'Map');
}

Check if Null

export function isNull(input: unknown): input is null {
    return input === null;
}

Check if Empty

export function isEmpty<T = unknown>(input: T): boolean {
    if (isArray(input) || isString(input)) {
        return input.length === 0;
    }
    if (input instanceof Map || input instanceof Set) {
        return input.size === 0;
    }
    if (isObjectLike(input)) {
        return Object.keys(input).length === 0;
    }
    return false;
}

Check if Function

export function isFunction(input: unknown): input is Function {
    return typeof input === 'function';
}

Check if Boolean

export function isBoolean(input: any): input is boolean {
    return matchesType(input, 'Boolean');
}

Check if Number

export function isNumber(input: unknown): input is number {
    return matchesType(input, 'Number');
}

Check if Date

export function isDate(input: unknown): input is Date {
    return matchesType(input, 'Date');
}

Check if RegExp

export function isRegExp(input: unknown): input is RegExp {
    return matchesType(input, 'RegExp');
}

Check if URL

export function isUrl(url: string): boolean {
    const pattern = /(((^https?:(?:\/\/)?)(?:[-;:&=\+\$,\w]+@)?[A-Za-z0-9.-]+(?::\d+)?|(?:www.|[-;:&=\+\$,\w]+@)[A-Za-z0-9.-]+)((?:\/[\+~%\/.\w-_]*)?\??(?:[-\+=&;%@.\w_]*)#?(?:[\w]*))?)$/;
    return pattern.test(url);
}

Check if Promise

export function isPromise<T = any>(input: any): input is Promise<T> {
    return matchesType(input, 'Promise') && isFunction(input.then) && isFunction(input.catch);
}

Check if JSON Object String

export function isJsonObjectString(str: string): str is string {
    if (!str) return false;
    return str.startsWith('{') && str.endsWith('}');
}

Check if Window Object

export function isWindowObject(input: any): input is Window {
    return typeof window !== 'undefined' && matchesType(input, 'Window');
}

Check if DOM Element

export function isDomElement(input: unknown): input is Element {
    return isObjectLike(input) && !!input.tagName;
}

Server Environmnet Check

export const isServer = typeof window === 'undefined';

Browser Environmetn Check

export const isBrowser = !isServer;