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Questions tagged [reselect]

Reselect is a selector library for Redux.

Reselect is a selector library which uses memoization. It was originally written to compute derived data from -like applications state, but it's not strictly coupled to any specific architecture/library.

Reselect keeps a copy of the last inputs/outputs of the last call, and recomputes the result ONLY IF one of the inputs changes. If the the same inputs are provided twice in a row, Reselect return the cached saved output.

Reselect's memoization and caching are fully customizable.

Resources

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Use reselect selector with parameters

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 =>…
Michal
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How to deal with relational data in Redux?

The app I'm creating has a lot of entities and relationships (database is relational). To get an idea, there're 25+ entities, with any type of relations between them (one-to-many, many-to-many). The app is React + Redux based. For getting data from…
Jordan Enev
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Reselect - selector that invokes another selector?

I have a selector: const someSelector = createSelector( getUserIdsSelector, (ids) => ids.map((id) => yetAnotherSelector(store, id), ); // ^^^^^ (yetAnotherSelector expects 2 args) That…
Patrickkx
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Is there a way to properly mock Reselect selectors for unit testing?

I'm having a pretty complex selectors structure in my project (some selectors may have up to 5 levels of nesting) so some of them are very hard to test with passing input state and I would like to mock input selectors instead. However I found that…
Eugene Tsakh
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Is there any place for OOP in redux?

I've been using object-oriented programming practices for 25 years and trying to move toward functional programming for the last 5 years, but my mind always goes towards OOP when I'm trying to do something complex and, especially now that ES6…
Sigfried
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How can I get ownProps using reselect on redux?

I want to create a selector with memoization using reselect based on some ownProps of mapStateToProps.
Sibelius Seraphini
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How to use Reselect selectors inside a Redux reducer

My app already has a large collection of selectors used by the various container objects. These are great for accessing different parts of the state and make refactoring the state much easier. Now I want to use my selectors inside some of my reducer…
burtyish
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How do you use `reselect` to memoize an array?

Suppose I have a redux store with this state structure: { items: { "id1" : { foo: "foo1", bar: "bar1" }, "id2": { foo: "foo2", bar: "bar2" } } } This store evolves by receiving full new values of…
phtrivier
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How to use createSelector with parameter and Typescript?

I use redux-toolkit to generate selectors. I want to use them in my own custom reselect selectors with parameters. But I do not know how to type the return type of my selector? const selectOrganizationName = (id: string): ??? => createSelector( …
tomole
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How to use reselect on a changing list, when the objects are the same?

I use reselect to get parts of my redux state. i have a list of objects in my state. One of my subselector for my create selector is a filter function of this list: state => state.list.filter(filterFunction) So i pass this to my…
bitrevolution
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Reselect - does it ever make sense to create a memorized selector which is just used to get part of the state?

I have a normal selector which is just used to get part of the state: export const getAllPosts = state => { return state.posts; }; If I use the reselect to wrap the selector: import { createSelector } from 'reselect'; export const allPosts =…
Jason Xu
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how to use selectors in redux app with TypeScript?

I try to use selectors from reselect library in my Redux app. my selectors file looks: import { createSelector } from 'reselect' const postsSelectors = state => state.global.posts.allPostse; export const getPosts = createSelector( […
SuperManEver
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How does reselect createStructuredSelector work in Typescript?

I’m trying to understand how the reselect method createStructuredSelector works in Typescript. I see this pattern a lot: export interface SomeProps { readonly property1: string; readonly property2: boolean; readonly property3:…
d0nutz1
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useSelector and reselect , which one is performance beneficial

For memoization/performance consideration, using useSelector with ShallowEqual. Will there be some more benefits for performance optimization using "Reselect/createSelector" option ? Or both the options are same ? Will have the data as JSON array…
dsi
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Use createSelector (or any memoized selector) with hooks without mapStateToProps

I want to create a memoized selector which will update automatically when the state in the redux store changes. I read about Reselect's createSelector here: https://redux.js.org/recipes/computing-derived-data I see that mapStateToProps is being used…
CodeMonkey
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