AI Prompts for TypeScript

What Are AI Prompts for TypeScript?

Picture this: you're migrating a JavaScript codebase to TypeScript. The migration guide says "add types gradually." But every AI-generated TypeScript snippet uses

any

any

strict: true

This is the most common TypeScript AI prompt failure: code that compiles but defeats the purpose of TypeScript. AI prompts for TypeScript need to enforce type safety explicitly — because the AI will optimize for compiling, not for the type safety guarantees you're actually after.

Why It Matters

TypeScript's value proposition is catching type errors at compile time rather than runtime. But that value is only realized when your types are actually specific. A codebase full of

any

Studies on large TypeScript codebases consistently show that projects with high

any

AI-generated TypeScript, without specific guidance, trends toward

any

⚡ Pro tip: Add "set strict: true in tsconfig assumptions — never use

any

as unknown as T

Building Your TypeScript Prompt

The core template for ai prompts typescript:

You are a TypeScript expert. Write strictly-typed TypeScript code for the following task.

TypeScript version: 5.x
tsconfig: strict mode enabled

Task: [describe what you're building]

Type requirements:
- No `any` types — use `unknown` if the type is truly unknown, then narrow it
- No non-null assertions (!) — handle null/undefined explicitly
- Define interfaces or types for all data structures (no inline object types in function signatures)
- Use generics where a function works with multiple types
- Discriminated unions for any value that can be one of several shapes

After the code:
- List every type decision that required a design choice and explain why you made it
- Flag any place where the types are technically correct but could be more specific

What this does: Forces the AI to reason through every type rather than substituting

any

Key TypeScript Prompt Patterns

For API response typing:

Write TypeScript types for this API response. Requirements:
- Use discriminated unions for responses that can be either success or error
- Make the success data type generic so it can be reused for different endpoints
- Use readonly where the data shouldn't be mutated after parsing
- Include a type guard function that validates the raw response matches the expected type at runtime

API response shape: [paste example JSON response]

What this does: API responses are the boundary where TypeScript's type system meets untyped reality. Type guards at this boundary catch malformed responses before they cause runtime errors deep in the application.

⚠️ Common mistake: Typing API responses as

any

For complex state management:

Write TypeScript types for an application state that can be in these states: loading, loaded (with data), error, and empty. Use a discriminated union so TypeScript can narrow the type based on the current state. The component should only be able to access `data` when the state is `loaded` — not in other states.

What this does: Discriminated unions make impossible states unrepresentable in TypeScript — which is one of the most valuable patterns in the language. Instead of checking

if (data && !loading && !error)

if (state.type === 'loaded')

data

⚡ Pro tip: For any TypeScript that handles form data or user input, ask: "Use Zod (or similar runtime validation library) alongside the TypeScript types. The Zod schema should match the TypeScript type exactly, so runtime validation and compile-time types are always in sync." TypeScript types don't survive

JSON.parse()

For utility types:

Write TypeScript utility types for the following common patterns in our codebase:
1. Make all properties of a type optional except for a specific list of required ones
2. Create a type that represents a "loading" state wrapper around any data type
3. Extract the resolved type from a Promise-returning function

Show the implementation and at least one usage example for each.

What this does: Utility types are where TypeScript gets genuinely powerful — and where AI assistance pays the most, because utility type syntax is unintuitive until you've written it a dozen times.

Common Mistakes

Accepting

any

any

any

unknown

Forgetting to type generic constraints. Unconstrained generics (

<T>

Missing return types on public functions. TypeScript can infer return types, but explicit return types on exported functions serve as documentation and catch type drift during refactoring. Add "always include explicit return types on exported functions."

Conclusion

TypeScript's value is proportional to how seriously you take your types. AI prompts that forbid

any

For teams maintaining TypeScript codebases, building a shared set of type patterns — utility types, API response types, state machine types — in a prompt library is high-use work. PromptABCD is worth using for your ai prompts typescript patterns so the institutional type knowledge lives in a tool the whole team can use, not in the one developer who figured it out last quarter.

TypeScript Migration Prompts

For teams migrating JavaScript to TypeScript, the "add types gradually" advice is correct but vague. A structured migration prompt makes it actionable:

Migrate this JavaScript file to TypeScript. Migration requirements:
1. Start with the loosest types that would compile — mark intentionally-unknown types with a TODO comment
2. Use JSDoc type imports for any third-party libraries that don't have @types packages
3. Do not change runtime behavior — only add type annotations
4. Flag any places where adding types revealed a potential runtime error
5. After migration, list the TODO comments in priority order — which should be tightened first?

JavaScript file: [paste]

What this does: Separates the migration into two phases — "make it compile" and "make the types meaningful" — which is more manageable than trying to write perfect types on the first pass. The TODO comments create a prioritized backlog for tightening types over time.

⚡ Pro tip: For TypeScript projects using monorepos, add: "All shared types should live in a types package, not in the consuming package. Identify any types in this code that should be extracted to the shared types package." Type sharing across packages is one of the most common monorepo TypeScript headaches — prompting for extraction early prevents the type duplication that makes refactoring painful.

Advanced TypeScript Patterns

TypeScript has a set of advanced patterns — template literal types, conditional types, infer keyword — that are genuinely difficult to write from scratch. AI assistance here pays off significantly:

Write a TypeScript utility type that [describe the transformation you need]. Show: the type implementation, two usage examples, and an explanation of how the type works in plain English. If there's a simpler alternative that covers 90% of the use cases without the complexity, show that too.

What this does: TypeScript's advanced type system is powerful but can become an unmaintainable type puzzle. Asking for a simpler alternative alongside the full solution gives you a pragmatic escape hatch — which is often the right call for a team that doesn't specialize in type-level programming.

⚡ Pro tip: Ask the AI to write a TypeScript configuration checklist for your project: 'Given our codebase (Node.js backend, strict mode), suggest the optimal tsconfig.json settings and explain what each non-default option does and why it's worth enabling. Flag any settings that would be too strict for our current codebase and need a migration plan.' tsconfig settings have a significant impact on TypeScript's bug-catching ability and are often left at defaults.

TypeScript's value compounds with codebase size. The larger the codebase, the more valuable precise types become as documentation and as bug prevention. Building your team's ai prompts typescript library early — with patterns for API types, state types, utility types, and migration strategies — creates a type-quality foundation that pays dividends for years.