Redux: Better way for private/public selectors












1














As this course suggests, private selectors are repeated as public selectors to be used on the full state.




  • Private selectors used on slice.

  • Public selectors used on full state.


But this will result in:




  • Repeating code

  • Flooding the the namespace of the public selectors


Is there a better way to organize selectors?



Original example:



Root Reducer & public selector:



// reducers/index.js
import todos, * as fromTodos from './todos';

// Reducer
export default combineReducers({
todos
});

// Private selector
getVisibleTodos(state, filter) {
return fromTodos.getVisibleTodos(state.todos, filter);
}


Slice Reducer & private selector:



// reducers/todos.js

// Reducer
export default (state, action) => {
switch(action.type){
case 'ADD_TODO':
// ...
break;
// Handle other actions ...
}
}

// Private selector
getVisibleTodos(state, filter) {
switch(filter) {
case 'all':
return todos;
case 'completed':
return state.filter(t => t.completed);
// Other cases ...
}
}


Using the selector:



const mapStateToProps = (state, {params}) => ({
todos: getVisibleTodos(state, params.filter || 'all')
});









share|improve this question
























  • Can you provide a working example?
    – David Lemon
    Nov 13 '18 at 10:00










  • I've enhanced the example. Notice redefining the selector once as private selector and another time as a public selector. The question is about avoiding this repetition.
    – Meena Alfons
    Nov 13 '18 at 10:15






  • 1




    Selectors are usually pure functions so can be moved to their own module without issue. For inspiration I'd look at reselect
    – Davin Tryon
    Nov 13 '18 at 10:22
















1














As this course suggests, private selectors are repeated as public selectors to be used on the full state.




  • Private selectors used on slice.

  • Public selectors used on full state.


But this will result in:




  • Repeating code

  • Flooding the the namespace of the public selectors


Is there a better way to organize selectors?



Original example:



Root Reducer & public selector:



// reducers/index.js
import todos, * as fromTodos from './todos';

// Reducer
export default combineReducers({
todos
});

// Private selector
getVisibleTodos(state, filter) {
return fromTodos.getVisibleTodos(state.todos, filter);
}


Slice Reducer & private selector:



// reducers/todos.js

// Reducer
export default (state, action) => {
switch(action.type){
case 'ADD_TODO':
// ...
break;
// Handle other actions ...
}
}

// Private selector
getVisibleTodos(state, filter) {
switch(filter) {
case 'all':
return todos;
case 'completed':
return state.filter(t => t.completed);
// Other cases ...
}
}


Using the selector:



const mapStateToProps = (state, {params}) => ({
todos: getVisibleTodos(state, params.filter || 'all')
});









share|improve this question
























  • Can you provide a working example?
    – David Lemon
    Nov 13 '18 at 10:00










  • I've enhanced the example. Notice redefining the selector once as private selector and another time as a public selector. The question is about avoiding this repetition.
    – Meena Alfons
    Nov 13 '18 at 10:15






  • 1




    Selectors are usually pure functions so can be moved to their own module without issue. For inspiration I'd look at reselect
    – Davin Tryon
    Nov 13 '18 at 10:22














1












1








1







As this course suggests, private selectors are repeated as public selectors to be used on the full state.




  • Private selectors used on slice.

  • Public selectors used on full state.


But this will result in:




  • Repeating code

  • Flooding the the namespace of the public selectors


Is there a better way to organize selectors?



Original example:



Root Reducer & public selector:



// reducers/index.js
import todos, * as fromTodos from './todos';

// Reducer
export default combineReducers({
todos
});

// Private selector
getVisibleTodos(state, filter) {
return fromTodos.getVisibleTodos(state.todos, filter);
}


Slice Reducer & private selector:



// reducers/todos.js

// Reducer
export default (state, action) => {
switch(action.type){
case 'ADD_TODO':
// ...
break;
// Handle other actions ...
}
}

// Private selector
getVisibleTodos(state, filter) {
switch(filter) {
case 'all':
return todos;
case 'completed':
return state.filter(t => t.completed);
// Other cases ...
}
}


Using the selector:



const mapStateToProps = (state, {params}) => ({
todos: getVisibleTodos(state, params.filter || 'all')
});









share|improve this question















As this course suggests, private selectors are repeated as public selectors to be used on the full state.




  • Private selectors used on slice.

  • Public selectors used on full state.


But this will result in:




  • Repeating code

  • Flooding the the namespace of the public selectors


Is there a better way to organize selectors?



Original example:



Root Reducer & public selector:



// reducers/index.js
import todos, * as fromTodos from './todos';

// Reducer
export default combineReducers({
todos
});

// Private selector
getVisibleTodos(state, filter) {
return fromTodos.getVisibleTodos(state.todos, filter);
}


Slice Reducer & private selector:



// reducers/todos.js

// Reducer
export default (state, action) => {
switch(action.type){
case 'ADD_TODO':
// ...
break;
// Handle other actions ...
}
}

// Private selector
getVisibleTodos(state, filter) {
switch(filter) {
case 'all':
return todos;
case 'completed':
return state.filter(t => t.completed);
// Other cases ...
}
}


Using the selector:



const mapStateToProps = (state, {params}) => ({
todos: getVisibleTodos(state, params.filter || 'all')
});






javascript redux react-redux






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share|improve this question




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edited Nov 13 '18 at 10:14







Meena Alfons

















asked Nov 13 '18 at 8:47









Meena AlfonsMeena Alfons

5231626




5231626












  • Can you provide a working example?
    – David Lemon
    Nov 13 '18 at 10:00










  • I've enhanced the example. Notice redefining the selector once as private selector and another time as a public selector. The question is about avoiding this repetition.
    – Meena Alfons
    Nov 13 '18 at 10:15






  • 1




    Selectors are usually pure functions so can be moved to their own module without issue. For inspiration I'd look at reselect
    – Davin Tryon
    Nov 13 '18 at 10:22


















  • Can you provide a working example?
    – David Lemon
    Nov 13 '18 at 10:00










  • I've enhanced the example. Notice redefining the selector once as private selector and another time as a public selector. The question is about avoiding this repetition.
    – Meena Alfons
    Nov 13 '18 at 10:15






  • 1




    Selectors are usually pure functions so can be moved to their own module without issue. For inspiration I'd look at reselect
    – Davin Tryon
    Nov 13 '18 at 10:22
















Can you provide a working example?
– David Lemon
Nov 13 '18 at 10:00




Can you provide a working example?
– David Lemon
Nov 13 '18 at 10:00












I've enhanced the example. Notice redefining the selector once as private selector and another time as a public selector. The question is about avoiding this repetition.
– Meena Alfons
Nov 13 '18 at 10:15




I've enhanced the example. Notice redefining the selector once as private selector and another time as a public selector. The question is about avoiding this repetition.
– Meena Alfons
Nov 13 '18 at 10:15




1




1




Selectors are usually pure functions so can be moved to their own module without issue. For inspiration I'd look at reselect
– Davin Tryon
Nov 13 '18 at 10:22




Selectors are usually pure functions so can be moved to their own module without issue. For inspiration I'd look at reselect
– Davin Tryon
Nov 13 '18 at 10:22












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