feat(react): add usage diff and benchmark coverage

README.md

@@ -29,6 +29,7 @@ bunx foresthouse --help
 - Honors the nearest `tsconfig.json` or `jsconfig.json`, including `baseUrl` and `paths`
 - Expands sibling workspace packages by default, including their own `tsconfig` alias rules
 - Analyzes React component and hook usage trees from explicit entry files or inferred Next.js app and pages routes
+- Shows React tree changes relative to a Git ref or range with `foresthouse react --diff`
 - Reads `package.json` manifests to show package-level dependency trees for single packages and monorepos
 - Shows dependency-tree changes relative to a Git ref or range with `foresthouse deps --diff`
 - Prints an ASCII tree by default, or JSON with `--json`
@@ -58,7 +59,7 @@ Options:
 ### Commands
 
 - `foresthouse import <entry-file>`: analyzes a JavaScript or TypeScript entry file and prints a dependency tree by following imports, re-exports, `require()`, and dynamic `import()`.
-- `foresthouse react [entry-file]`: analyzes React component, hook, and render relationships and prints a React usage tree. It also supports automatic Next.js entry discovery with `--nextjs`.
+- `foresthouse react [entry-file]`: analyzes React component, hook, and render relationships and prints a React usage tree. It also supports automatic Next.js entry discovery with `--nextjs`, plus Git-based tree diffs with `--diff`.
 - `foresthouse deps <directory>`: reads `package.json` manifests and workspace structure from a package directory and prints a package dependency tree. Use `--diff` to show only changes relative to a Git ref or range.
 
 ### Example
@@ -107,6 +108,7 @@ Usage:
   $ foresthouse react [entry-file] [options]
 
 Options:
+  --diff <git-ref-or-range>  Show only React tree changes relative to a Git revision or range.
   --cwd <path>     Working directory used for relative paths.
   --config <path>  Explicit tsconfig.json or jsconfig.json path.
   --nextjs         Infer Next.js page entries from app/ and pages/ when no entry is provided.
@@ -118,6 +120,19 @@ Options:
   -h, --help       Display this message
 ```
 
+React diff mode compares React usage graphs rather than raw file text diffs. A single ref like `--diff HEAD~3` compares that tree to the current working tree, while ranges such as `HEAD~3..HEAD` or `origin/dev...HEAD` compare two committed Git trees.
+
+Example React diff output:
+
+```text
+~ apps/site/pages/index.tsx:21:45
+~ <Home /> [component] (apps/site/pages/index.tsx)
+└─ ~ <Hero /> [component] (apps/site/src/features/Main/Hero/Hero.tsx)
+   └─ + useForm() [hook] (react-hook-form)
+```
+
+In this example, the page entry itself is unchanged as source text, but its reachable React graph changed because `<Hero />` started calling `useForm()`.
+
 ### `foresthouse deps --help`
 
 Analyzes package-level dependency trees for both single-package projects and monorepos. Use `--diff` to show only dependency changes relative to a Git ref or range.
@@ -137,6 +152,8 @@ Common examples:
 - `foresthouse import src/main.ts`
 - `foresthouse import --entry src/main.ts --cwd test/fixtures/basic`
 - `foresthouse react src/App.tsx`
+- `foresthouse react src/App.tsx --diff origin/dev...HEAD`
+- `foresthouse react pages/index.tsx --cwd . --diff HEAD~3..HEAD`
 - `foresthouse react --nextjs --cwd .`
 - `foresthouse deps .`
 - `foresthouse deps ./packages/a`
@@ -270,3 +287,4 @@ pnpm run check
 
 - Unit tests live next to source files as `src/**/*.spec.ts`.
 - End-to-end command tests live under `e2e/`.
+- Benchmarks live next to analyzers as `src/**/*.bench.ts` and run with `pnpm exec vitest bench --run --config vitest.bench.config.ts`.

bench/helpers.ts

@@ -0,0 +1,79 @@
+import { execFileSync } from 'node:child_process'
+import fs from 'node:fs'
+import os from 'node:os'
+import path from 'node:path'
+
+const temporaryDirectories: string[] = []
+
+let cleanupRegistered = false
+const GIT_EXEC_MAX_BUFFER = 64 * 1024 * 1024
+
+export function createGitRepository(
+  prefix: string,
+  commits: readonly {
+    readonly message: string
+    readonly files: Readonly<Record<string, string>>
+  }[],
+): string {
+  registerCleanup()
+
+  const repositoryRoot = fs.mkdtempSync(path.join(os.tmpdir(), prefix))
+  temporaryDirectories.push(repositoryRoot)
+
+  runGit(repositoryRoot, ['init', '--initial-branch=main'])
+  runGit(repositoryRoot, ['config', 'user.name', 'Foresthouse Benchmarks'])
+  runGit(repositoryRoot, ['config', 'user.email', 'benchmarks@example.com'])
+
+  commits.forEach((commit) => {
+    replaceRepositoryFiles(repositoryRoot, commit.files)
+    runGit(repositoryRoot, ['add', '-A'])
+    runGit(repositoryRoot, ['commit', '-m', commit.message])
+  })
+
+  return repositoryRoot
+}
+
+function replaceRepositoryFiles(
+  repositoryRoot: string,
+  files: Readonly<Record<string, string>>,
+): void {
+  fs.readdirSync(repositoryRoot, { withFileTypes: true }).forEach((entry) => {
+    if (entry.name === '.git') {
+      return
+    }
+
+    fs.rmSync(path.join(repositoryRoot, entry.name), {
+      recursive: true,
+      force: true,
+    })
+  })
+
+  Object.entries(files).forEach(([relativePath, fileContent]) => {
+    const absolutePath = path.join(repositoryRoot, relativePath)
+    fs.mkdirSync(path.dirname(absolutePath), { recursive: true })
+    fs.writeFileSync(absolutePath, fileContent)
+  })
+}
+
+function runGit(repositoryRoot: string, args: readonly string[]): string {
+  return execFileSync('git', args, {
+    cwd: repositoryRoot,
+    encoding: 'utf8',
+    maxBuffer: GIT_EXEC_MAX_BUFFER,
+    stdio: ['ignore', 'pipe', 'pipe'],
+  }).trim()
+}
+
+function registerCleanup(): void {
+  if (cleanupRegistered) {
+    return
+  }
+
+  cleanupRegistered = true
+
+  process.on('exit', () => {
+    temporaryDirectories.splice(0).forEach((directory) => {
+      fs.rmSync(directory, { recursive: true, force: true })
+    })
+  })
+}

e2e/deps.test.ts

@@ -44,6 +44,7 @@ const pnpmMonorepoFixtureDirectory = path.join(
   'deps-pnpm-monorepo',
 )
 const temporaryDirectories: string[] = []
+const GIT_EXEC_MAX_BUFFER = 64 * 1024 * 1024
 
 afterEach(() => {
   temporaryDirectories.splice(0).forEach((directory) => {
@@ -1078,6 +1079,7 @@ function runGit(repositoryRoot: string, args: readonly string[]): string {
   return execFileSync('git', args, {
     cwd: repositoryRoot,
     encoding: 'utf8',
+    maxBuffer: GIT_EXEC_MAX_BUFFER,
     stdio: ['ignore', 'pipe', 'pipe'],
   }).trim()
 }