How do I clear states or empty array on click in react 0.14 ES6?

I found the problem is my closeModal didn’t get called at all on closing modal. I am doing that to closeModal on componentWillUnmount function. I understood that the below code causes problem.

this.state.myArray=[] // class component
const[myArray, setMyArray]=useState([]) // functional component

I changed it back to

this.setState({myArray: []}); // class component
setMyArray([]); // functional component

You can as well use this to clear array without using setState:

   this.state.your_array.length = 0;

This will work in any function.