define-it 🔍
Prevent runtime ReferenceError: keyword is not defined crashes before they hit production.
define-it is a fast, zero-configuration VS Code extension that scans your JavaScript and TypeScript files in real-time. It is designed especially for teams working with Git (pulling, merging, and cherry-picking), where missing declarations or conflicts often slip past local build tools and are only discovered during runtime sanity tests.
🚀 Key Features
- ⚡ On-Save Static AST Scan: Scans your files in milliseconds upon save using a lightweight AST-based lexical scope analyzer.
- 🌿 Proactive Git Diff Scanning: Automatically detects and scans files modified between your working branch and previous git actions (pulls, checkouts, merges, or cherry-picks) to flag newly introduced ReferenceErrors.
- 🛠️ Workspace-Wide Global Resolution: Intelligently parses non-module script files across your workspace to gather global declarations, eliminating false positives for legacy script-based projects.
- ⚙️ Custom Globals Ignore List: Define your own globals (like
jQuery, $, or proprietary workspace variables) directly in VS Code settings.
- 📁 Integrated Problems Panel: Diagnostics are output directly to VS Code's native Problems view, allowing you to double-click and jump straight to the offending undefined variable.
📸 How it Works
When you type and save code with an undeclared reference, define-it highlights it:
// console.js
console.log(myUndeclaredVar); // ⚠️ ReferenceError: 'myUndeclaredVar' is not defined.
The error is instantly pushed to the Problems view:
⚙️ Configuration & Settings
You can customize define-it behavior by searching for define-it in VS Code Settings (Ctrl+,):
| Setting |
Type |
Default |
Description |
define-it.customGlobals |
string[] |
[] |
List of custom global variables to ignore during static analysis (e.g., ['jQuery', 'myCustomGlobal']). |
define-it.ignorePaths |
string[] |
[] |
Additional directory/file paths to ignore during scanning (e.g., ['vendor', 'public/temp']). node_modules, dist, build, and .git are ignored by default. |
⌨️ Commands
Open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P on macOS) and run:
Define-It: Scan Git-Changed Files: Manually scans files that have changes between your current HEAD and HEAD@{1} or index (highly useful right after running a git pull or git cherry-pick).Define-It: Scan Workspace: Performs a full scan of all supported JavaScript and TypeScript files in the active workspace.
📂 Supported Languages
- JavaScript (
.js, .jsx)
- TypeScript (
.ts, .tsx)
🛠️ Development & Contributing
If you'd like to run the extension locally or contribute:
- Clone the repository.
- Run
npm install to install dependencies.
- Press
F5 to launch the extension in the Extension Development Host.
- Run tests:
npm run test
📄 License
MIT License.
