avoid-deep-merge

avoid-deep-merge.js

 updateState({target}) {
       this.setState(prevState => {
          return {
            user: {
              ...prevState.user,
              [target.name]: target.value,
              address: {
               // first lay out all the properties within the address object
                ...prevState.user.address,
               // now, overwrite the properties that need to be overwritten...
               // each of the below statements are optional depending upon what needs to be overwritten
               // street: 'a new street'
               // city: 'a new city'
              }
            }
          }
        }, () => doSomething())
 }