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

NEVER mutate this.state directly, as calling setState() afterwards may replace the mutation you made. Treat this.state as if it were immutable.

use Object.assign for clone object

const newState = Object.assign({}, this.state, {
  something: 'b'
})

this.setState(newState)

Or you can merge current state:

this.setState({
  something: 'a',
  something2: 'b', 
})