React: can you use setState with existing state object?

Question

Lets say I have a React component that has a \"state\" with 10 fields:

this.state = {
    field1: 1,
    field2: 2,
    ... other fields
    something: \'a\'
};
         


        

Answer 1

You would actually mark all the members of State as optional.

interface State {
  field1?: number, 
  field2?: number,
}

This is not as unsafe as you might think. TypeScript added the concept of freshness to support this pattern and others.

More

This is covered here :

https://basarat.gitbooks.io/typescript/content/docs/types/freshness.html#use-case--react-state