Add transformResponse Prop for Response Format Modification

[moghani81]

User Story

As a developer, I want to use a transformResponse prop to process and modify server responses, so that I can decode encoded responses or apply custom transformations as needed before they are rendered in MapLibre.

Rationale

Many servers return responses in encoded or customized formats (e.g., compressed, encrypted, or containing metadata). There is currently no direct way to preprocess these responses before they are used in MapLibre.

Impact

Developers will continue to struggle with implementing custom logic to handle server responses, leading to fragmented and inconsistent solutions across projects. This could limit the adoption of MapLibre in scenarios requiring customized response handling.

• Improved developer experience with a flexible and extensible API.
• Easier integration with a wide variety of server configurations.
• Reduced need for manual intervention in network handling, resulting in cleaner codebases.

Proposed Solution

Introduce a transformResponse prop in MapLibre, which would allow developers to define a custom transformation function. This function will take the raw server response as input and return the transformed data.

const map = new maplibregl.Map({
  container: 'map',
  style: 'https://example.com/styles.json',
  transformResponse: (response) => {
    // Example: Decode Base64
    const decoded = atob(response);
    return JSON.parse(decoded);
  },
});

By implementing this feature, MapLibre can better support modern use cases and offer flexibility to developers without adding significant complexity.

[HarelM]

I believe this is available using addProtocol...?