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name: typescript description: TypeScript guidelines covering type safety, RORO pattern, complexity limits, and error handling patterns. Use when writing TypeScript code.

TypeScript Development

Apply these guidelines when working with TypeScript code.

Types

Avoid using 'any'

Never use the any type. Always provide proper types.

Do not define inline object types

Do not define object/record types inline in parameter lists or return types. Create a named type/interface (or import an existing one) and use that name in the signature. Do the same for return shapes (e.g. Promise<Result> not Promise<{…}>).

Copy// Bad
async execute(args: { sessionId: string; voiceId: string }): Promise<{ sessionAudioId: string }> { … }

// Good
export type ExecuteArgs = {
  sessionId: string;
  voiceId: string;
};

export type ExecuteResult = {
  sessionAudioId: string;
};

export async function execute(args: ExecuteArgs): Promise<ExecuteResult> {
  …
}

Use 'is' and 'has' prefixes for booleans

Boolean variables and functions should use is or has prefixes (e.g., isActive, hasPermission).

Functions

Use the RORO pattern

Receive an object, return an object.

Complexity

Keep cyclomatic complexity below 6

If you have a large switch case, consider strategy pattern/dispatch table.

Do not chain more than 2 array iteration methods

Store as variable and continue on next line if more processing is needed.

Do not nest blocks more than 3 levels deep

Keep nesting shallow for better readability.