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small-rules

No Useless Use Memo

Suggestion
small-rules/no-useless-use-memo

Disallow useMemo calls that only wrap values static enough to live at module scope.

Diagnostic Messages

uselessUseMemo
useMemo is wrapping a static value. Move the value to module scope instead of paying hook overhead for no runtime benefit.

Configuration

This rule accepts one options object after the severity.

dependencyModeOptional

Dependency-array mode used to decide whether a memoized value is static.

Type
"empty-or-omitted" | "non-updating" | "aggressive"
Default
non-updating
environmentOptional

The React environment: 'roblox-ts' uses @rbxts/react, 'standard' uses react.

Type
"roblox-ts" | "standard"
Default
roblox-ts
staticGlobalFactoriesOptional

Global constructors and factories whose calls are treated as static values.

Type
Array<string>
Default
{
  "jsPlugins": [
    "@pobammer-ts/small-rules"
  ],
  "rules": {
    "small-rules/no-useless-use-memo": [
      "error",
      {
        "dependencyMode": "non-updating",
        "environment": "roblox-ts",
        "staticGlobalFactories": [
          "Axes",
          "BrickColor",
          "CFrame",
          "Color3",
          "ColorSequence",
          "ColorSequenceKeypoint",
          "DateTime",
          "Enum",
          "Faces",
          "NumberRange",
          "NumberSequence",
          "NumberSequenceKeypoint",
          "PathWaypoint",
          "PhysicalProperties",
          "Ray",
          "Rect",
          "Region3",
          "Region3int16",
          "TweenInfo",
          "UDim",
          "UDim2",
          "Vector2",
          "Vector3",
          "Vector3int16",
          "Vector3int32"
        ]
      }
    ]
  }
}

Examples

Memoized constant computation
import { useMemo } from "react";


const value = useMemo(() => {
  return 1;
}, []);
Memoized theme-dependent value
import { useMemo } from "react";
import { AnimationLibrary, SpringConfiguration, getAnimationConfiguration } from "./animation-config";


function Component({ theme }) {
  const value = useMemo(() => getAnimationConfiguration(theme, AnimationLibrary.ReactSpring), [theme]);
    return value;
  }
No Useless Use SpringRelatedBoth ban hook wrappers whose values are static enough to leave the hook entirely.No Unused Use MemoRelatedUnused memos and static-value memos both pay hook cost for no preserved value.No Use Memo Simple ExpressionOverlapsTrivial expressions and fully-static expressions can both be flagged as pointless memos.No New Instance In Use MemoRelatedMemoizing Instance construction is a Roblox-specific useMemo correctness concern.