className helper

cn.js

/**
 * Function that takes any number of strings or records of booleans or functions that return booleans
 * and returns a string of class names that are true.
 * @param classes
 * @returns
 */
export function cn(...classes) {
  return classes
    .flatMap(c =>
      typeof c === 'string'
        ? c
        : Object.entries(c)
            .filter(([, v]) => (typeof v === 'function' ? v() : v))
            .map(([k]) => k)
    )
    .join(' ')
}

cn.ts

/**
 * Function that takes any number of strings or records of booleans or functions that return booleans
 * and returns a string of class names that are true.
 * @param classes
 * @returns
 */
export function cn(...classes: Array<string | Record<string, boolean | (() => boolean)>>): string {
  return classes
    .flatMap(c =>
      typeof c === 'string'
        ? c
        : Object.entries(c)
            .filter(([, v]) => (typeof v === 'function' ? v() : v))
            .map(([k]) => k)
    )
    .join(' ')
}