re-reselect

library5.1.0jsnpmunverified

A lightweight wrapper around Reselect that provides deeper memoization and cache management for selectors. Current stable version is 5.1.0. Since Reselect v5, many re-reselect features are now native in Reselect, but re-reselect continues to offer backward compatibility and custom caching strategies. It maintains a cache of Reselect selectors keyed by a user-defined key selector, allowing different calls with different arguments to hit separate caches. Compared to bare Reselect, re-reselect prevents cache invalidation when switching between different argument values, making it ideal for sharing selectors across multiple component instances or sequentially calling selectors with varying parameters.

testing

npm install re-reselect

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · RE-RESELECT

re-reselect

testingjavascriptv5.1.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

createCachedSelector

✓ import { createCachedSelector } from 're-reselect';

✗ import createCachedSelector from 're-reselect';

re-reselect exports createCachedSelector as a named export, not a default export.

createStructuredCachedSelector

✓ import { createStructuredCachedSelector } from 're-reselect';

✗ const createStructuredCachedSelector = require('re-reselect').createStructuredCachedSelector;

CommonJS require of named export works, but ESM named import is preferred in modern projects.

FlatCacheObject

✓ import { FlatCacheObject } from 're-reselect';

Type-only import: import type { FlatCacheObject } from 're-reselect'; Available when using TypeScript.

Demonstrates createCachedSelector with a keySelector based on libraryName, showing cache retention across different argument values.

import { createCachedSelector } from 're-reselect'; const getUsers = (state) => state.users; const getLibraryId = (state, libraryName) => state.libraries[libraryName]?.id; const getUsersByLibrary = createCachedSelector( getUsers, getLibraryId, (users, libraryId) => users.filter(user => user.libraryId === libraryId) )( (state, libraryName) => libraryName ); const state = { users: [ { id: 1, libraryId: 10 }, { id: 2, libraryId: 20 }, ], libraries: { react: { id: 10 }, vue: { id: 20 }, }, }; const reactUsers = getUsersByLibrary(state, 'react'); const vueUsers = getUsersByLibrary(state, 'vue'); const reactUsersAgain = getUsersByLibrary(state, 'react'); console.log(reactUsers === reactUsersAgain); // true - cache hit

Debug

Known issues

gotchare-reselect v5+ requires reselect v5 as a peer dependency. Using older reselect versions may cause unexpected behavior or TypeScript errors.

fix

yarn add reselect@^5.0.0 or npm install reselect@^5.0.0

affects: >=5.0.0

deprecatedFrom reselect v5, many re-reselect features are natively available. Re-reselect is maintained for backward compatibility but may not receive new features.

fix

Consider switching to native reselect createSelector with custom memoize options if you don't need backward compatibility.

affects: >=5.0.0

gotchaThe keySelector is required and must return a valid cache key. If it returns undefined, every call will create a new selector without caching.

fix

Ensure keySelector returns a primitive (string, number) or a value compatible with the chosen cache object.

affects: *

breakingIn re-reselect v4, the default cache object was changed from LruCacheObject to FlatCacheObject by default, which may break code relying on LRU eviction behavior.

fix

Pass { cacheObject: new LruCacheObject({ maxSize: 5 }) } as option to restore LRU behavior.

affects: >=4.0.0 <5.0.0

gotchaWhen using TypeScript, the createCachedSelector type inference may not be perfect with complex selectors. You may need to manually type the keySelector or use 'as any' in some edge cases.

fix

Cast keySelector return type explicitly or use type assertions with caution.

affects: *

Errors

Common errors & fixes

TypeError: (0 , re_reselect_1.createCachedSelector) is not a function

Default import used instead of named import. re-reselect does not have a default export in ESM.

fix

Use named import: import { createCachedSelector } from 're-reselect';

Cannot find module 're-reselect' or its corresponding type declarations.

Missing TypeScript types or incorrect version. re-reselect ships types, but may need @types/reselect installed separately.

fix

Install reselect and its types if using TypeScript: npm install reselect @types/reselect re-reselect

Uncaught Error: re-reselect expects 'reselect' as a peer dependency but is missing.

Missing peer dependency reselect. re-reselect requires reselect installed alongside.

fix

Install reselect: npm install reselect

Selector creators (createCachedSelector) expect a keySelector function as second argument, but got undefined.

KeySelector not provided or returned undefined. KeySelector is required and must return a valid key.

fix

Pass a keySelector function that returns a primitive (e.g., (state, arg) => arg.id).

Upgrade

Version history

5.1.0latest on npm

Audit

Dependencies

reselectrequiredpeer dependency - re-reselect wraps reselect and requires it to be installed separately

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/toomuchdesign/re-reselect ↗

packagere-reselect ↗

homepagehttps://github.com/toomuchdesign/re-reselect#readme ↗