stringifyClasses.tsx

/**
 * This function accepts array of strings or strings or both
 * all empty or falsy values are omitted
 * returns a string of classes
 *@example
 // 1) simple use case: single argument - array of strings
    stringifyClasses([
        styles.day,
        isPassive && styles.dayPassive,
        disabled && styles.dayDisabled,
        !isPassive && isToday && styles.dayToday,
        isStartOfWeek && styles.dayStartOfWeek,
        isEndOfWeek && styles.dayEndOfWeek,
        isStartOfMonth && styles.dayStartOfMonth,
        isEndOfMonth && styles.dayEndOfMonth,
    ])
 // 2) simple use case: multiple arguments - variadic strings
    stringifyClasses(
        styles.day,
        isPassive && styles.dayPassive,
        disabled && styles.dayDisabled,
        !isPassive && isToday && styles.dayToday,
        isStartOfWeek && styles.dayStartOfWeek,
        isEndOfWeek && styles.dayEndOfWeek,
        isStartOfMonth && styles.dayStartOfMonth,
        isEndOfMonth && styles.dayEndOfMonth,
    )
 // 3) complex use case: multiple mixed arguments - variadic strings + variadic arrays
    stringifyClasses(
        styles.day,
        isPassive && styles.dayPassive,
        [
            disabled && styles.dayDisabled,
            [ !isPassive && [ isToday && styles.dayToday ] ], // multiple nesting is allowed (max 5 levels)
            isStartOfWeek && styles.dayStartOfWeek,
            isEndOfWeek && styles.dayEndOfWeek
        ],
        isStartOfMonth && styles.dayStartOfMonth,
        isEndOfMonth && styles.dayEndOfMonth,
    )
 // 4) classNames prop provided: apply classNames or a default class
    stringifyClasses(
        classNames || styles.day,
    )
 // 5) optional block of classes case: removes whole block of classes if condition is falsy
    stringifyClasses(
        styles.day,
        isPassive && styles.dayPassive,
        props.disabled && [
            styles.dayDisabled,
            [ !isPassive && [ isToday && styles.dayToday ] ],
            isStartOfWeek && styles.dayStartOfWeek,
            isEndOfWeek && styles.dayEndOfWeek
        ],
        isStartOfMonth && styles.dayStartOfMonth,
        isEndOfMonth && styles.dayEndOfMonth,
    )
 */
export function stringifyClasses<T extends unknown[]>(...classesArray: T) {
    return classesArray.flat(5).filter(Boolean).join(' ')
}