modernize repo - esm, vitest, biome

.biomeignore

@@ -0,0 +1,7 @@
+node_modules
+lib
+dist
+**/fixtures/**
+src/fixtures
+**/*.test.ts
+**/*.map

.claude/settings.local.json

@@ -0,0 +1,13 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(npm test)",
+      "Bash(npm test:*)",
+      "Bash(pnpm exec:*)",
+      "Bash(pnpm lint:*)",
+      "Bash(pnpm biome:ci:*)",
+      "Bash(grep:*)"
+    ],
+    "deny": []
+  }
+}

.github/workflows/ci.yml

@@ -1,21 +1,30 @@
 name: CI
+
 on:
-  - push
-  - pull_request
+  push:
+    branches: [ main, modernize-repo ]
+  pull_request:
+    branches: [ main ]
+
 jobs:
   test:
-    name: Node.js ${{ matrix.node-version }}
     runs-on: ubuntu-latest
     strategy:
-      fail-fast: false
       matrix:
-        node-version:
-          - 14
-          - 12
+        node-version: [20.x, 22.x, 24.x]
+
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
-        with:
-          node-version: ${{ matrix.node-version }}
-      - run: npm install
-      - run: npm test
+    - uses: actions/checkout@v4
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v4
+      with:
+        node-version: ${{ matrix.node-version }}
+    - uses: pnpm/action-setup@v3
+      with:
+        version: latest
+        run_install: true
+    - run: pnpm typecheck
+    - run: pnpm lint
+    - run: pnpm build
+    - name: Run tests
+      run: pnpm test

.github/workflows/prerelease.yml

@@ -0,0 +1,46 @@
+name: Publish Pre-release
+
+on:
+  pull_request:
+    branches: [ main ]
+    types: [opened, synchronize, reopened]
+
+jobs:
+  build-and-publish:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.pull_request.head.repo.full_name == github.repository }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          registry-url: 'https://registry.npmjs.org'
+      - uses: pnpm/action-setup@v3
+        with:
+          version: latest
+          run_install: true
+      - run: pnpm typecheck
+      - run: pnpm lint
+      - run: pnpm build
+      - name: Run tests
+        run: pnpm test
+
+      - name: Get PR commit count
+        id: pr_commits
+        run: |
+          count=$(gh pr view ${{ github.event.pull_request.number }} --json commits --jq '.commits | length')
+          echo "commit_count=$count" >> "$GITHUB_OUTPUT"
+        env:
+          GH_TOKEN: ${{ github.token }}
+
+      - name: Update version for pre-release
+        run: |
+          PACKAGE_VERSION=$(node -p "require('./package.json').version")
+          PRERELEASE_VERSION="${PACKAGE_VERSION}-pr${{ github.event.number }}.${{ steps.pr_commits.outputs.commit_count }}"
+          npm version $PRERELEASE_VERSION --no-git-tag-version
+          echo "Publishing version: $PRERELEASE_VERSION"
+
+      - name: Publish pre-release to npm
+        run: pnpm publish --tag pr --no-git-checks --no-otp
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/publish.yml

@@ -0,0 +1,27 @@
+name: Publish to npm
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          registry-url: 'https://registry.npmjs.org'
+      - uses: pnpm/action-setup@v3
+        with:
+          version: latest
+          run_install: true
+      - run: pnpm typecheck
+      - run: pnpm lint
+      - run: pnpm build
+      - name: Run tests
+        run: pnpm test
+      - run: pnpm publish --no-git-checks --no-otp
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.gitignore

@@ -12,3 +12,4 @@ node_modules/
 .yarnrc
 
 
+fixutres/main.*

CLAUDE.md

@@ -0,0 +1,114 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Commands
+
+### Installation
+
+```bash
+# Install dependencies
+pnpm install
+```
+
+### Development
+
+```bash
+# Start the CLI tool with ts-node (for development)
+pnpm start
+```
+
+### Build
+
+```bash
+# Build the project (outputs to ./lib)
+pnpm build
+```
+
+### Testing
+
+```bash
+# Run all tests and linting
+pnpm test
+
+# Run tests in watch mode
+pnpm test:watch
+
+# Run specific test file
+pnpm vitest run path/to/test-file.test.ts
+
+# Run tests with coverage
+pnpm vitest run --coverage
+
+# Run linting
+pnpm lint
+
+# Format code
+pnpm format
+```
+
+## Module System
+
+This project uses ECMAScript Modules (ESM). Key implications:
+
+- Import statements require file extensions (e.g., `import { foo } from './bar.js'`)
+- The `package.json` includes `"type": "module"` to indicate ESM usage
+- TypeScript is configured with `"module": "NodeNext"` and `"moduleResolution": "NodeNext"`
+
+## Project Structure
+
+Source Map Diff is a utility that compares JavaScript source maps to understand why a bundle's size changed. It can analyze sourcemaps from local files or web URLs and provides output in HTML, JSON, or console formats.
+
+### Architecture
+
+The project has a modular architecture with these key components:
+
+1. **CLI Interface** (`src/cli/`) - Handles command-line arguments and outputs results
+2. **Source Map Loading** (`src/load-source-map/`) - Loads source maps from filesystem or web URLs
+3. **File Size Comparison** (`src/compare-file-sizes/`) - Compares file sizes between two source maps
+4. **Tree Generation** (`src/generate-tree/`) - Converts comparison data into tree visualizations
+5. **Core Module** (`src/source-map-diff.ts`) - Orchestrates the process and exposes the main API
+
+### Core Workflow
+
+1. Load source maps from provided locations (local files or URLs)
+2. Parse the source maps to extract file sizes
+3. Compare file sizes between the two source maps
+4. Generate a tree visualization of the differences
+5. Output the results in the requested format (HTML, JSON, or console)
+
+### API Functions
+
+- `sourceMapDiff({ currentSrc, previousSrc })` - Returns raw comparison data
+- `sourceMapDiffAsHtml({ currentSrc, previousSrc })` - Returns HTML visualization
+- `sourceMapDiffForConsole({ currentSrc, previousSrc })` - Returns console-friendly output
+
+## Usage Examples
+
+### CLI Usage
+
+```bash
+# Compare two local source maps
+pnpm run start --previousSrc path/to/old-file.js --currentSrc path/to/new-file.js
+
+# Compare with HTML output format
+pnpm run start --previousSrc path/to/old-file.js --currentSrc path/to/new-file.js --format html
+
+# Compare with JSON output format
+pnpm run start --previousSrc path/to/old-file.js --currentSrc path/to/new-file.js --format json
+```
+
+### API Usage
+
+```typescript
+import { sourceMapDiff, sourceMapDiffAsHtml, sourceMapDiffForConsole } from 'source-map-diff';
+
+// Get raw comparison data
+const data = await sourceMapDiff({ previousSrc: 'path/to/old-file.js', currentSrc: 'path/to/new-file.js' });
+
+// Get HTML output
+const html = await sourceMapDiffAsHtml({ previousSrc: 'path/to/old-file.js', currentSrc: 'path/to/new-file.js' });
+
+// Get console-friendly output
+const consoleOutput = await sourceMapDiffForConsole({ previousSrc: 'path/to/old-file.js', currentSrc: 'path/to/new-file.js' });
+```