no-unused-use-memo

Reports useMemo calls whose return value is ignored.

Rule details Problem

This rule reports useMemo(...) when it is used as a standalone statement, including void useMemo(...). If you are running side effects, use useEffect. If you need memoization, keep and use the returned value.

By default, the rule looks for React imports in the roblox-ts environment. Set environment to "standard" to use react instead.

useMemo is not an effect hook

A discarded memo value usually means the hook is being used for side effects or to dodge effect rules.

Options

| Option | Type | Default | What it does | | ------------- | ------------ | ----------- | ------------- | -------------------------------------------- | | environment | "roblox-ts" | "standard" | "roblox-ts" | Chooses which React package imports to track |

Examples

Incorrect

import { useMemo } from "react";

useMemo(() => {
  trackAnalytics();
}, [eventName]);

void useMemo(() => buildConfig(eventName), [eventName]);

Correct

import { useEffect, useMemo } from "react";

useEffect(() => {
  trackAnalytics();
}, [eventName]);

const config = useMemo(() => buildConfig(eventName), [eventName]);

Related rules

require-named-effect-functions Requires named effect callbacks

no-useless-use-memo Moves static memo values to module scope

use-exhaustive-dependencies Checks hook dependency lists

React Docs: useMemo Official reference for useMemo