mapStateToProps()
is a utility which helps your component get updated state (which is updated by some other components):
const mapStateToProps = (state) => {
return {
todos: getVisibleTodos(state.todos, state.visibilityFilter)
}
}
mapDispatchToProps()
is a utility which will help your component to fire an action event (dispatching action which may cause change of application state):
const mapDispatchToProps = (dispatch) => {
return {
onTodoClick: (id) => {
dispatch(toggleTodo(id))
}
}
}
Recommend always using the “object shorthand” form for the mapDispatchToProps
Redux wrap it in another function that looks like (…args) => dispatch(onTodoClick(…args)), and pass that wrapper function as a prop to your component.
const mapDispatchToProps = ({
onTodoClick
})