## Task 1


type Movie = {
    name: string,
    actors: Array<ActorId>
};

type Actor = { name: string };

type Rating = { value: number };

declare function getMovie(id: MovieId): Promise<Movie>;
declare function getActor(id: ActorId): Promise<Actor>;
declare function getMovieRating(id: MovieId): Promise<Rating>;

type MovieData = {
    movieName: string,
    actorNames: Array<string>,
    rating: number
};

async function getData(id: MovieId): Promise<MovieData> {
    const movie = await getMovie(id);
    const movieRating = await getMovieRating(id);
    
    const actors = [];
    
    for (actorId of movie.actors) {
        const actorName = await getActor(actorId);
        actors.push(actorName)
    }
    
    return {
        movieName: movie.name,
        actorNames: actors,
        rating: movieRating
    }
}

## Task 2

type Props = {
    list: Array<string>,
    onItemClick: string => void
};

class List extends Component<Props> {
    onClickHandler = item => () => {
        this.props.onItemClick(item)
    }

    render() {
        const {
            list,
            onItemClick
        } = this.props;
        
        return (
            <ul>
                {list.map(item => (
                    <li key={item} onClick={this.onClickHandler(item)}>{item}</li>
                ))}
            </ul>
        )
    
        // ...
    }
}

## Task 3

type State = {
    checkedItem: null | string;
}

class Alphabet extends PureComponent<{}, State> {
    constructor(props) {
        super(props);
        this.state = {
            checkedItem: null
        };
    }
        
    static list = ['a', 'b', 'c'];

    setCheckedItem = (item: string) => {
        this.setState({
            checkedItem: item
        });
    }

    render() {
        return (
            <List
                list={list}
                onItemClick={ this.setCheckedItem }
            />
        );
    }
}

## Task 4

    
const symbolDict = {
    '(': ')',
    '{': '}',
    '[': ']'
};
    
function validate(str: string): boolean {
    const stack = [];
    const symbolArray = str.split('');
    
    for (let i = 0; i < symbolArray.length; i++) {
        if (symbolDict.hasOwnProperty(symbolArray[i])) {
            stack.push(symbolDict[symbolArray[i]]);
        } else if (symbolArray[i] !== stack.pop()) {
            return false;
        }
    }
    
    return stack.length === 0;
}

validate('[ ]'); // -> true
validate('('); // -> false
validate('( ) [ ]'); // -> true
validate('( [) ]'); // -> false
validate('{ { { ( ( [ ( ) ] ) ) } } }'); // -> true
validate('( { { { ( ( [ ( ) ] ) ) } } }'); // -> false