Missing “key” prop for element. (ReactJS and TypeScript)

You are rendering an array of elements, so React needs a key prop (see react docs) to identify elements and optimize things.

Add key={topic.id} to your jsx:

return (
  <div>
    <h2>Results List</h2>
    {topics.map((topic: any) =>
      <div className="panel panel-default" key={topic.id}>
        <div className="panel-heading">{topic.name}</div>
        <div className="panel-body">{topic.description}</div>
      </div>
    )}
  </div>
);