foo.jsSomeConnectedComponent.js

// SomeConnectedComponent.js
// ============================
// Before:
const mapDispatchToProps = (dispatch) => ({
  dispatch,
})

const mapStateToProps = (state) => ({
  resumable: (state.exam.attempt.attemptUUID !== null),

const mergeProps = (stateProps, dispatchProps, ownProps) => {
  const startOrResume = (stateProps.resumable) ?
    examResumeAndUpdateAttempt : examStartAndCreateAttempt
  return Object.assign(
    {},
    dispatchProps,
    ownProps,
    {
      startOrResume,
      dispatch: dispatchProps.dispatch,
    }
  )
}

export default connect(mapStateToProps, mapDispatchToProps, mergeProps)(Preparation)
// ============================

// After:
const mapStateToProps = (state) => {
  const resumable = state.exam.attempt.attemptUUID !== null
  const startOrResume = resumable ? examResumeAndUpdateAttempt : examStartAndCreateAttempt
  return { startOrResume }
}

export default connect(mapStateToProps)(Preparation)
// ============================