What are the best practices for implementing the stencil store?

When creating a Stencil store, is there a best practice when defining fields?

The documentation online only has basic examples of numbers, but what if we have objects, strings or booleans? Should we be using ‘as’ or ‘new’ keywords?

const { state, onChange } = createStore({
  username: null as string,
  friends: new List<Friends>(),
  isActive: false as boolean,