问题
How do I pass additional parameters to combined selectors? I am trying to
• Get data
• Filter data
• Add custom value to my data set / group data by myValue
export const allData = state => state.dataTable
export const filterText = state => state.filter.get('text')
export const selectAllData = createSelector(
allData,
(data) => data
)
export const selectAllDataFiltered = createSelector(
[ selectAllData, filterText ],
(data, text) => {
return data.filter(item => {
return item.name === text
})
}
)
export const selectWithValue = createSelector(
[ selectAllDataFiltered ],
(data, myValue) => {
console.log(myValue)
return data
}
)
let data = selectWithValue(state, 'myValue')
console.log(myValue)
returns undefined
回答1:
The answer to your questions is detailed in an FAQ here: https://github.com/reactjs/reselect#q-how-do-i-create-a-selector-that-takes-an-argument
In short, reselect doesn't support arbitrary arguments passed to selectors. The recommended approach is, instead of passing an argument, store that same data in your Redux state.
回答2:
what about returning a function from selector? getFilteredToDos
is an example for that
// redux part
const state = {
todos: [
{ state: 'done', text: 'foo' },
{ state: 'time out', text: 'bar' },
],
};
// selector for todos
const getToDos = createSelector(
getState,
(state) => state.todos,
);
// selector for filtered todos
const getFilteredToDos = createSelector(
getToDos,
(todos) => (todoState) => todos.filter((toDo) => toDo.state === todoState);
);
// and in component
const mapStateToProps = (state, ownProps) => ({
...ownProps,
doneToDos: getFilteredToDos()('done')
});
回答3:
Another option:
const parameterizedSelector = (state, someParam) => createSelector(
[otherSelector],
(otherSelectorResult) => someParam + otherSelectorResult
);
And then use like
const mapStateToProps = state => ({
parameterizedSelectorResult: parameterizedSelector(state, 'hello')
});
I am not sure about memoization/performance in this case though, but it works.
来源:https://stackoverflow.com/questions/40291084/use-reselect-selector-with-parameters