context.js

const reducer = (state, action) => {
  const { results } = state;
  switch (action.type) {
    case 'DELETE_ELEMENT':
      return {
        ...state,
        results: results.filter(result => {
          return result.email !== action.payload;
        })
      };
    case 'ADD_CONTACT':
      return {
        ...state,
        localUsers: [action.payload, ...state.localUsers]
      };
    default:
      return state;
  }
};