The Component
is defined like so:
interface Component<P = {}, S = {}> extends ComponentLifecycle<P, S> { }
Meaning that the default type for the state (and props) is: {}
.
If you want your component to have value
in the state then you need to define it like this:
class App extends React.Component<{}, { value: string }> {
...
}
Or:
type MyProps = { ... };
type MyState = { value: string };
class App extends React.Component<MyProps, MyState> {
...
}