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Overview

Devark supports both JavaScript and TypeScript for all modules. When you add a module to your project, Devark prompts you to choose your preferred language and generates the appropriate files with correct dependencies.

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When to Choose JavaScript

JavaScript is ideal when you want to move quickly without type annotations. Perfect for:
  • Small projects or MVPs
  • Simple APIs without complex data structures
  • Teams without TypeScript experience
  • Projects where build speed is critical
JavaScript projects require:
  • No tsconfig.json configuration
  • No TypeScript compiler setup
  • Fewer development dependencies
  • No type definition packages (@types/*)

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When to Choose TypeScript

TypeScript provides compile-time type checking and enhanced IntelliSense:
  • Catch errors before runtime
  • Better autocompletion in editors
  • Refactoring with confidence
  • Self-documenting code through types
TypeScript excels in:
  • Projects with multiple developers
  • Complex business logic
  • Long-term maintenance
  • Integration with typed libraries

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How Language Selection Works

When you install any Devark module, you’ll see this prompt: 
? Which version do you want to add for this module?
  > JavaScript
    TypeScript
Devark then:
  1. Detects or prompts for entry file
    • JavaScript: app.js (root directory)
    • TypeScript: src/app.ts (inside src/ folder)
  2. Installs language-specific dependencies
    • JavaScript: Only runtime dependencies
    • TypeScript: Adds typescript, ts-node, and @types/* packages
  3. Generates files with correct extensions
    • JavaScript: .js files in root directory
    • TypeScript: .ts files in src/ directory
Devark auto-detects TypeScript entry files by searching for .ts files in the src/ directory if your specified entry file isn’t found.

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File Structure Differences

my-project/
├── app.js                    # Entry point
├── config/
│   └── googleStrategy.js
├── routes/
│   └── googleAuthRoutes.js
├── controllers/
│   └── otp.js
├── middleware/
│   └── ratelimit.js
├── .env
├── .gitignore
└── package.json
All generated files live in the root directory alongside your entry file.

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Code Generation Examples

Devark generates language-appropriate code for each module. Here’s how the same Google OAuth strategy looks in both languages: 
import passport from 'passport'
import { Strategy as GoogleStrategy } from 'passport-google-oauth20'

passport.use(new GoogleStrategy({
  clientID: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  callbackURL: '/auth/google/callback',
}, (accessToken, refreshToken, profile, done) => {
  // Replace this with DB logic
  return done(null, profile)
}))

passport.serializeUser((user, done) => {
  done(null, user)
})

passport.deserializeUser((user, done) => {
  done(null, user)
})
Notice how TypeScript version includes:
  • Type annotations for all parameters
  • Interface definitions (IUser)
  • Explicit return types
  • Non-null assertions (!) for environment variables

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Dependency Differences

Devark automatically installs the correct dependencies based on your language choice:
Runtime dependencies only:
{
  "dependencies": {
    "express": "^4.18.0",
    "passport": "^0.6.0",
    "passport-google-oauth20": "^2.0.0",
    "express-session": "^1.17.0",
    "dotenv": "^16.0.0"
  }
}

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Migration Guide

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Starting with JavaScript

If you’re unsure which to choose, start with JavaScript:
  1. Install modules with JavaScript option
  2. Build your features quickly
  3. Migrate to TypeScript later if needed

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Migrating to TypeScript

When you’re ready to adopt TypeScript:
1

Install TypeScript dependencies

npm install --save-dev typescript ts-node @types/node @types/express
2

Create tsconfig.json

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "lib": ["ES2020"],
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}
3

Create src/ directory

mkdir src
4

Rename files incrementally

Start with your entry file:
mv app.js src/app.ts
Then gradually rename other files:
mv routes/googleAuthRoutes.js src/routes/googleAuthRoutes.ts
mv config/googleStrategy.js src/config/googleStrategy.ts
5

Add type annotations

Update files with TypeScript syntax as you encounter type errors.
6

Re-install modules in TypeScript

For any new modules, choose TypeScript when prompted by Devark.
You can run JavaScript and TypeScript side-by-side during migration. TypeScript can import JavaScript files without issues.

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Best Practices

JavaScript Projects

  • Keep files organized in folders (routes, controllers, config)
  • Use JSDoc comments for basic type hints
  • Leverage ES6+ features
  • Consider migrating to TS as project grows

TypeScript Projects

  • Enable strict mode in tsconfig.json
  • Define interfaces for API responses
  • Use enums for constants
  • Leverage utility types (Partial, Pick, Omit)

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Source Code Reference

Devark’s language selection logic is implemented in:
  • src/modules/*/install.js - Module installation with language prompts (lines 36-47)
  • src/utils/packageManager.js - Dependency installation logic
  • Template files in templates/javascript/ and templates/typescript/ directories
Devark maintains separate template directories for JavaScript and TypeScript versions of every module, ensuring you always get properly typed code.

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