Frontend/src/classNames.ts

export interface ObjectClassNames {
    [index: string]: boolean;
}

export type ClassName = number | string | ObjectClassNames | false | null | undefined;

export default function classNames(...classNames: ClassName[]) {
    let result: string[] = [];

    classNames.forEach((item: ClassName): void => {
        if(!item) {
            return;
        }
        switch(typeof item) {
            case 'string':
                result.push(item);
                break;
            case 'object':
                Object.keys(item).forEach((key: string) => {
                    if(item[key]) {
                        result.push(key);
                    }
                });
                break;
            default:
                result.push(`${item}`);
        }
    });

    return result.join(' ');
}