10 Battle-Tested Prompts for JavaScript and TypeScript Code Generation (React, Node.js, Utilities)

Introduction

Every developer I know uses AI to generate code daily. But there's a gap between "write a function that sorts an array" and getting production-ready, typed, tested JavaScript or TypeScript. The difference? A well-crafted prompt. After spending the last two years refining prompts for JS/TS code generation — across React components, Node.js backends, and utility libraries — I've compiled a collection of prompts that actually work. These aren't hypothetical. They're prompts I use in my own workflow at ASI Biont, where we generate hundreds of lines of AI-assisted code weekly.

In this article, you'll get 10 concrete prompts for JavaScript and TypeScript code generation, each with a real usage example. No fluff, no theory. Just prompts that produce clean, typed, and maintainable code.

Why Prompts Matter for JS/TS Generation

JavaScript and TypeScript are among the most popular languages for AI code generation — and for good reason. Their dynamic nature (JS) and rich type system (TS) make them ideal for pattern-based generation. However, without precise prompts, you often get:

• Unsafe code — missing null checks, ignoring edge cases
• Untyped functions — TypeScript becomes any-script
• Overly generic solutions — not tailored to your framework (React, Express, etc.)

A good prompt acts like a specification. It tells the model the context (framework, environment), constraints (type strictness, error handling), and output format (function signature, JSDoc).

According to a 2025 study by GitHub, developers who use structured prompts for code generation see a 40% reduction in review cycles (source: GitHub Blog, "The State of AI Code Generation," 2025).

Prompt 1: Generate a React Component with TypeScript

Prompt:

Generate a React component in TypeScript that renders a search input with debounced onChange. The component should accept a placeholder prop and a onSearch callback. Use useCallback and useEffect for debouncing (300ms). Include proper types for props. Add a loading state via an isLoading prop. Return JSX with an input element and a loading spinner (inline CSS).

Real usage example:
I needed a search bar for our internal dashboard at ASI Biont. This prompt produced a DebouncedSearch component with correct typing, debounce logic, and a spinner. I just copied it, adjusted the spinner CSS, and it worked.

Why it works: The prompt specifies the framework (React), language (TypeScript), hooks (useCallback, useEffect), debounce timing, props shape, and even the output format (JSX with inline CSS). No ambiguity.

Prompt 2: Generate a TypeScript Utility Function with Generics

Prompt:

Write a TypeScript utility function called 'groupBy' that takes an array of objects and a key selector function. The function should return a Map where keys are the result of the selector and values are arrays of matching objects. Use generics to ensure type safety: T for the item type, K for the key type. Include JSDoc comments. Handle empty arrays gracefully. Add unit test examples in comments.

Real usage example:
We needed to group API responses by status code. The generated groupBy function worked immediately with our typed response objects. The generic constraint K extends string | number prevented runtime errors.

Key insight: Adding "Include unit test examples in comments" forces the model to think about edge cases (empty array, null selector).

Prompt 3: Generate Express.js Middleware with Error Handling

Prompt:

Generate an Express.js middleware function in TypeScript that validates a JSON request body against a Joi schema. The middleware should return a 400 error with validation details if validation fails. Use async/await. Define a custom error class 'ValidationError' that extends Error. Export the middleware as default. Add proper TypeScript types for Request, Response, NextFunction.

Real usage example:
I was building a REST API for user registration. This prompt gave me a validateBody middleware with Joi integration, proper async error handling (caught by Express 5's built-in error handler), and typed errors. Saved me 20 minutes of boilerplate.

Note: If you're using a different validation library (Zod, Yup), just replace "Joi" in the prompt. The model adapts.

Prompt 4: Generate a React Custom Hook with TypeScript

Prompt:

Create a React custom hook called 'useLocalStorage' in TypeScript. It should accept a key (string) and an initial value (generic type T). The hook should return a tuple [value, setValue] similar to useState. Persist the value to localStorage on every change. Handle JSON parse errors gracefully by falling back to the initial value. Add a listener for storage events (cross-tab sync). Include proper cleanup in useEffect.

Real usage example:
We used this hook to persist user preferences (theme, sidebar state) across sessions. The cross-tab sync feature was a bonus — when users changed settings in one tab, the other tab updated automatically. The generated code handled the storage event listener correctly.

Pro tip: Adding "Handle JSON parse errors gracefully" prevents the hook from crashing when localStorage contains corrupted data.

Prompt 5: Generate a Node.js CLI Tool with Commander

Prompt:

Generate a Node.js CLI tool using Commander.js in TypeScript. The tool should have a command 'generate' that takes a required argument 'name' and optional flags '--type' (string, default 'component') and '--dir' (string, default './src'). The command should create a file with a basic template based on the type. Use chalk for colored output. Include error handling for missing directories. Export the program.

Real usage example:
Our team needed a scaffolding CLI for new React components. This prompt produced a fully functional CLI with Commander, argument parsing, file creation logic, and colored console output. We extended it to support multiple templates.

Why Commander? It's the most popular CLI framework for Node.js, and the model knows its API well.

Prompt 6: Generate a TypeScript Type Guard

Prompt:

Write a TypeScript type guard function called 'isApiResponse' that checks if an unknown value is of type { status: number; data: unknown; message?: string }. The function should use a custom type predicate (value is ApiResponse). Include runtime checks for each field. Add a unit test example with a valid and invalid response.

Real usage example:
When consuming third-party APIs, runtime validation is critical. This type guard helped us safely narrow types after fetching data from an external service. The prompt's focus on "runtime checks" ensured the generated code didn't just declare a type but actually verified it.

Prompt 7: Generate a React Form with Validation (Formik + Yup)

Prompt:

Generate a React form component in TypeScript using Formik and Yup validation. The form should have fields: email (string, required, valid email), password (string, required, min 8 chars), and confirmPassword (string, must match password). Use useFormik hook. Display inline error messages below each field. Style with Tailwind CSS classes. Include a submit handler that logs values to console.

Real usage example:
Building a login form for our SaaS product. The prompt produced a complete form with validation, error display, and Tailwind classes. The only change I made was replacing the console.log with an API call.

Note: The model knows Formik's useFormik API and Yup's schema syntax. If you prefer React Hook Form, just replace "Formik" in the prompt.

Prompt 8: Generate a TypeScript Decorator for Logging

Prompt:

Write a TypeScript method decorator called 'LogExecutionTime' that logs the execution time of a method. The decorator should work with async methods (return a wrapped promise). Use console.time and console.timeEnd. Add a prefix parameter (string) for the log label. Include proper typing for the descriptor. Export the decorator.

Real usage example:
We needed to profile slow API endpoints. This decorator was attached to controller methods, and the generated code correctly handled both sync and async methods. The prefix parameter allowed us to identify each endpoint in logs.

Caution: TypeScript decorators are still experimental (stage 2). The prompt works with experimentalDecorators: true in tsconfig.

Prompt 9: Generate a WebSocket Client with Reconnection Logic

Prompt:

Generate a TypeScript class 'WebSocketClient' that wraps the native WebSocket API. It should support: auto-reconnection with exponential backoff (max 5 retries), custom event emitters (onMessage, onOpen, onClose, onError), a send method with JSON serialization, and a close method. Use a generic type for messages. Include a ping/pong keep-alive mechanism every 30 seconds.

Real usage example:
Our real-time dashboard needed a resilient WebSocket connection. The generated class handled reconnection, kept the connection alive with pings, and emitted typed events. The exponential backoff prevented server overload during outages.

Prompt 10: Generate a Performance-Optimized Array Chunk Function

Prompt:

Write a JavaScript function 'chunkArray' that splits an array into chunks of a specified size. The function should be optimized for large arrays (avoid spread operator in loops). Use a while loop with slice. Handle edge cases: size <= 0 returns empty array, empty array returns empty array. Add TypeScript types via JSDoc. Include a benchmark comment showing O(n) complexity.

Real usage example:
We process large datasets (100k+ records) in chunks for batch API calls. The generated function used Array.prototype.slice in a while loop, which is memory-efficient. The JSDoc types allowed us to use it in a TypeScript project without modification.

Comparison Table: Prompt Effectiveness

Note: Time saved is based on my personal experience. Your mileage may vary.

Common Pitfalls When Generating JS/TS Code

Even with great prompts, you can get bad output. Here are three issues I've encountered and how to fix them:

1. Missing imports — The model often assumes modules are available. Always check imports (e.g., React, Formik, Joi). Add "Include all import statements" to your prompt.

2. Overly verbose code — Sometimes the model adds redundant checks. If that happens, add "Keep the code concise."

3. Wrong TypeScript version — Features like satisfies (TS 4.9+) or using (TS 5.2+) might not be supported in your project. Specify your TypeScript version in the prompt, e.g., "Use TypeScript 5.0 compatible syntax."

How to Adapt Prompts for Your Own Use

The prompts above are templates. You can customize them by:

• Replacing libraries — Swap Formik for React Hook Form, Joi for Zod
• Changing output format — Add "Return as a single file" or "Split into multiple files"
• Adding constraints — "No external dependencies except React" or "Must pass ESLint with recommended rules"
• Specifying environment — "For Node.js 20+" or "For browser (ES2022)"

Real-World Case Study: Building a Dashboard with Generated Code

At ASI Biont, we built a real-time analytics dashboard using AI-generated code. Here's the breakdown:

Problem: We needed a dashboard with live data updates, user authentication, and data visualization. The deadline was tight (2 weeks).

Solution: I used prompts similar to the ones above to generate:
- React components (Prompt 1 & 7) for the UI
- WebSocket client (Prompt 9) for real-time data
- Express middleware (Prompt 3) for API validation
- Utility functions (Prompt 2 & 10) for data processing

Result: The core functionality was generated in 3 days. We spent the remaining time on integration, testing, and edge cases. The final dashboard passed code review with minor changes.

Key takeaway: AI-generated code is not a replacement for understanding, but it's a massive accelerator. The prompts acted as a specification that reduced ambiguity.

Conclusion

These 10 prompts are my go-to arsenal for JavaScript and TypeScript code generation. They cover the most common patterns: React components, custom hooks, Node.js middleware, CLI tools, type guards, forms, decorators, WebSocket clients, and utility functions. Each prompt is battle-tested in real projects at ASI Biont.

The secret isn't the prompt length — it's the specificity. A good prompt tells the model the context, constraints, and expected output. Next time you need to generate JS/TS code, try one of these prompts. You'll get production-ready code faster.

If you're working with data APIs and need to connect services like Salesforce, Google Analytics, or Stripe, ASI Biont supports seamless integration through our API platform. For more details, visit asibiont.com/courses.

Happy coding — and may your prompts be ever precise.