Redux: Getting Functional on Your Apps

With just callbacks or promises, one can almost read the code as non-functional, with a few extra parens 'n things thrown in. If you ignore the yellow parts below, it could almost be C or Java.

whatever.then(()=>{
      code
      code
      code
})

"then"... the code in curly braces happens.


But in Redux, we get things like this fragment from https://github.com/reduxjs/redux/blob/master/examples/todos/src/containers/VisibleTodoList.js


const mapDispatchToProps = dispatch => ({
  toggleTodo: id => dispatch(toggleTodo(id))
})

export default connect(
  mapStateToProps,
  mapDispatchToProps
)(TodoList)

Here, mapDispatchToProps is a function which takes a function (dispatch) as its argument
and returns an object who's property's value is also a function.

Then mapDispatchToProps is used as an argument to the connect(..) function
which returns a function whose argument is TodoList, a component which is also a function.


So if you don't understand that functions can be values, you'll hardly be able to function.