Eisland Dev Refactor Module Split

Refactor Module Split

Split a monolithic React component file into a clean module structure with five subdirectories: components/, hooks/, utils/, types/, and config/, plus an index.ts entry point.

When to use

• A single .tsx file has grown large and contains multiple concerns (utility functions, hooks, sub-components, constants, type definitions)
• The user explicitly asks to split/refactor a component into subdirectories
• The file is a React component that mixes UI rendering, state management, utility logic, and configuration

Process

Step 0: Ensure module scaffolding exists

Before extracting any code, verify the target module directory has the required structure. If any of the following are missing, create them first:

<module>/
├── index.ts          (if missing, create with placeholder export)
├── types/            (if missing, create directory)
├── config/           (if missing, create directory)
├── utils/            (if missing, create directory)
├── hooks/            (if missing, create directory)
└── components/       (if missing, create directory)

• Empty directories should contain a .gitkeep placeholder
• index.ts should initially export the original component (update after refactoring)

Step 1: Analyze the source file

Read the target file in full. Categorize every piece of code into one of five buckets:

Also check if the file's sibling directories already exist (e.g., components/ or hooks/ may already have files from prior refactoring). Don't duplicate existing extractions.

Step 2: Create the extracted files

For each extracted piece, create a new file in the appropriate directory. Every file must include:

1. License header — copy the exact GPL-3.0 block from the source file
2. File-level JSDoc — @file, @description, @author tags
3. Function/type JSDoc — @param, @returns for all exported functions
4. Correct imports — relative paths back to shared types or store slices

Naming conventions:

• types/ — camelCase with module prefix (e.g., todoTypes.ts, albumTypes.ts, localFileSearchTypes.ts)
• config/ — camelCase with module prefix (e.g., todoConfig.ts, albumConfig.ts, localFileSearchConfig.ts)
• utils/ — camelCase with module prefix (e.g., todoUtils.ts, albumUtils.ts, localFileSearchUtils.ts)
• hooks/ — camelCase with use prefix (e.g., useTodos.ts, useAlbumItems.ts, useLocalFileSearch.ts)
• components/ — PascalCase component name (e.g., TodoTab.tsx, TodoHeader.tsx, AlbumGridItem.tsx)

Step 3: Define types first

Create types/<module>Types.ts before other files. This file must contain:

1. Domain types — data models, enums, union types used by the module
2. Hook return type — Use<Module>Return interface describing the hook's full return shape
3. Component prop interfaces — <Component>Props for every sub-component

All component prop interfaces and hook return types MUST be defined in types/, not inline in component or hook files.

Example pattern:

// types/todoTypes.ts

/** 紧急程度 */
export type Priority = 'P0' | 'P1' | 'P2';

/** 单条待办 */
export interface TodoItem { ... }

/** useTodos hook 返回值类型 */
export interface UseTodosReturn { ... }

/** TodoHeader 组件入参 */
export interface TodoHeaderProps { ... }

/** TodoInputBar 组件入参 */
export interface TodoInputBarProps { ... }

Step 4: Rewrite the source file

Replace the extracted code in the original file with imports from the new modules. The source file should become a thin composition layer that:

• Imports hook from ../hooks/use<Module>
• Imports sub-components from ./<ComponentName>
• Calls the hook at the top level
• Destructures hook return values and passes them as props to sub-components
• Contains no extracted logic, no useEffect, no utility functions

Step 5: Create the index.ts entry point

Create <module>/index.ts that re-exports the main component:

export { TodoTab } from './components/TodoTab';

Step 6: Verify

Run these checks in order — all must pass before committing:

# 1. TypeScript compilation
npx tsc --noEmit --pretty

# 2. Comment standards compliance (file headers, JSDoc)
npm run comment:check

# 3. i18n completeness (all t() keys exist in both zh-CN and en-US)
npm run i18n:check

# 4. Unit tests
npm run test

If any check fails, fix the issue before proceeding. Common failures:

• comment:check — missing license header, missing @file/@description/@author, missing JSDoc on exported functions
• i18n:check — a t('key') call references a key not present in both locale files
• test — a refactored import path broke a test, or an extracted function changed behavior

Step 7: Commit

Use a conventional commit message:

refactor(<module-name>): extract types, utils, hooks, components, config from <OriginalFile>

- types/<name>Types.ts: type definitions + component prop interfaces
- utils/<name>Utils.ts: <what it does>
- hooks/use<Name>.ts: <what it does>
- components/<Name>.tsx: <what it does>
- config/<name>Config.ts: <what it contains>
- index.ts: module entry point
- <OriginalFile>.ts: simplified from <N> to <M> lines

Directory structure

feature/
├── index.ts                    (module entry point, re-exports main component)
├── types/
│   └── featureTypes.ts         (types, hook return type, component prop interfaces)
├── config/
│   └── featureConfig.ts        (constants, store keys, defaults)
├── utils/
│   └── featureUtils.ts         (pure utility functions)
├── hooks/
│   └── useFeature.ts           (all state management logic)
└── components/
    ├── FeatureTab.tsx           (thin composition layer: hook + sub-components)
    ├── FeatureHeader.tsx        (sub-component)
    └── FeatureList.tsx          (sub-component)

Real examples from the codebase

todo/
├── index.ts
├── types/todoTypes.ts
├── config/todoConfig.ts
├── utils/todoUtils.ts
├── hooks/useTodos.ts
└── components/
    ├── TodoTab.tsx
    ├── TodoHeader.tsx
    ├── TodoInputBar.tsx
    ├── TodoList.tsx
    ├── TodoItem.tsx
    └── TodoSubItem.tsx

album/
├── index.ts
├── types/albumTypes.ts
├── config/albumConfig.ts
├── utils/albumUtils.ts
├── hooks/
│   ├── useAlbumItems.ts
│   ├── useAlbumViewer.ts
│   ├── useAlbumViewerActions.ts
│   ├── useAlbumSelection.ts
│   ├── useAlbumGridConfig.ts
│   └── useAlbumDrag.ts
└── components/
    ├── AlbumTab.tsx
    ├── AlbumHeader.tsx
    ├── AlbumOverview.tsx
    ├── AlbumViewer.tsx
    ├── AlbumGridItem.tsx
    ├── AlbumMetaPanel.tsx
    └── AlbumSelectionBar.tsx

localFileSearch/
├── index.ts
├── types/localFileSearchTypes.ts
├── config/localFileSearchConfig.ts
├── utils/localFileSearchUtils.ts
├── hooks/useLocalFileSearch.ts
└── components/
    ├── LocalFileSearchTab.tsx
    ├── LocalFileSearchHeader.tsx
    ├── LocalFileSearchRootRow.tsx
    ├── LocalFileSearchQueryRow.tsx
    ├── LocalFileSearchConfigPanel.tsx
    └── LocalFileSearchResults.tsx

Acceptance criteria

Every extracted file MUST satisfy ALL of the following before the refactoring is considered complete.

Comment standards (references/COMMENT_STANDARDS.md)