@c15t/react V1.0.0 (or Whatever Version Applies)

Apr 25, 2025 by ADMIN 49 views

@c15t/react v1.0.5: Resolving TypeScript Type Incompatibility Issues

In this article, we will delve into the issue of TypeScript type incompatibility in the @c15t/react library, specifically with version 1.0.5. We will explore the problem, its causes, and provide solutions to resolve the issue, ensuring a seamless development experience.

The severity of this issue is classified as Low, indicating a minor inconvenience. The affected version is 1.0.5.

To reproduce the issue, follow these steps:

Run npx c15t init to initialize the @c15t/react library.
Host the @c15t library on a fully managed service, such as consent.io (Recommended).
Create a consent.io account if necessary.
Store the backend URL in a .env file and set it to YES.

The generated configuration should typecheck successfully out of the box.

However, when attempting to typecheck the generated configuration, TypeScript throws an error:

Type '{ mode: "c15t"; backendURL: string | undefined; }' does not satisfy the expected type 'ConsentManagerOptions'.
  Types of property 'backendURL' are incompatible.
    Type 'string | undefined' is not assignable to type 'string'.
      Type 'undefined' is not assignable to type 'string'.ts(1360)

This error occurs because process.env.X is inferred as string | undefined, but ConsentManagerOptions.backendURL expects a string.

To resolve this issue, we can employ one of the following solutions:

Option 1: Inline Fallback (Recommended for DX)

backendURL: process.env.NEXT_PUBLIC_C15T_URL ?? '',

This solution satisfies the type system but may hide misconfigurations (e.g., empty string sent as URL).

Option 2: Add a Runtime Check with a Throw (Safer)

const backendURL = process.env.NEXT_PUBLIC_C15T_URL;
if (!backendURL) {
  throw new Error('Missing NEXT_PUBLIC_C15T_URL in environment');
}

export const c15tConfig: ConsentManagerOptions = {
  mode: 'c15t',
  backendURL,
} satisfies ConsentManagerOptions;

This solution ensures the app crashes early in development if the environment variable is missing, preventing misconfigurations from being deployed silently.

Option 3: Loosen the Type

Modify ConsentManagerOptions to allow string | undefined, but this weakens the contract and pushes responsibility elsewhere.

Option 4 (Recommended): Allow Undefined in Types, Enforce at Runtime in the Provider

This solution involves:

Allowing undefined in types
Enforcing a runtime check in the ConsentManagerProvider

This approach provides a cleaner initial development experience (no need to juggle ?? '' or runtime throws in every config file), a type-safe runtime check living in a single, predictable place (the ConsentManagerProvider), and centralized error handling, making it easier to update logic or provide helpful hints.

In conclusion, the @c15t/react library version 1.0.5 exhibits a TypeScript type incompatibility issue. By understanding the problem and its causes, we can employ one of the proposed solutions to resolve the issue, ensuring a seamless development experience. The recommended solution involves allowing undefined in types and enforcing a runtime check in the ConsentManagerProvider, providing a cleaner initial development experience and centralized error handling.
@c15t/react v1.0.5: Q&A on Resolving TypeScript Type Incompatibility Issues

In our previous article, we explored the issue of TypeScript type incompatibility in the @c15t/react library, specifically with version 1.0.5. We provided solutions to resolve the issue, ensuring a seamless development experience. In this article, we will address frequently asked questions (FAQs) related to the issue and its resolution.

Q: What is the cause of the TypeScript type incompatibility issue in @c15t/react v1.0.5?

A: The issue arises from the fact that process.env.X is inferred as string | undefined, but ConsentManagerOptions.backendURL expects a string. This incompatibility leads to a TypeScript error.

Q: Which solution is recommended for resolving the issue?

A: Option 4 (Allow undefined in types, enforce at runtime in the provider) is the recommended solution. This approach provides a cleaner initial development experience, a type-safe runtime check living in a single, predictable place (the ConsentManagerProvider), and centralized error handling.

Q: What are the benefits of using Option 4?

A: The benefits of using Option 4 include:

Cleaner initial development experience (no need to juggle ?? '' or runtime throws in every config file)
Type-safe runtime check living in a single, predictable place (the ConsentManagerProvider)
Centralized error handling, making it easier to update logic or provide helpful hints

Q: How do I implement Option 4 in my code?

A: To implement Option 4, you need to:

Allow undefined in types
Enforce a runtime check in the ConsentManagerProvider

Here's an example implementation:

// Allow undefined in types
export const c15tConfig: ConsentManagerOptions = {
  mode: 'c15t',
  backendURL: process.env.NEXT_PUBLIC_C15T_URL,
} satisfies ConsentManagerOptions;

// Enforce a runtime check in the ConsentManagerProvider
const backendURL = process.env.NEXT_PUBLIC_C15T_URL;
if (!backendURL) {
  throw new Error('Missing NEXT_PUBLIC_C15T_URL in environment');
}

Q: Can I use Option 1 (Inline fallback) as a temporary solution?

A: Yes, you can use Option 1 (Inline fallback) as a temporary solution. However, keep in mind that this approach may hide misconfigurations (e.g., empty string sent as URL).

Q: What are the implications of using Option 3 (Loosen the type)?

A: Using Option 3 (Loosen the type) weakens the contract and pushes responsibility elsewhere. This approach may lead to more complex error handling and debugging.

Q: How do I update my code to use the recommended solution (Option 4)?

A: To update your code to use the recommended solution (Option 4), follow these steps:

Allow undefined in types
Enforce a runtime check in the ConsentManagerProvider

Here's an example implementation:

// Allow undefined in types
export const c15tConfig: ConsentManagerOptions = {
  mode: 'c15',
  backendURL: process.env.NEXT_PUBLIC_C15T_URL,
} satisfies ConsentManagerOptions;

// Enforce a runtime check in the ConsentManagerProvider
const backendURL = process.env.NEXT_PUBLIC_C15T_URL;
if (!backendURL) {
  throw new Error('Missing NEXT_PUBLIC_C15T_URL in environment');
}