…hin the `WP_Theme_JSON` class. Let's break down the changes and their impact.

**Problem:** The original `sanitize` method likely performed redundant computations when called multiple times with the same input.  Sanitizing theme JSON data can be resource-intensive, especially with complex themes or frequent calls.

**Solution:**  The added code addresses this inefficiency by implementing a simple caching mechanism. Before performing the sanitization, the method now checks if the input has already been processed.

**How the Cache Works:**

1. **Hashing the Input:** The `md5` function generates a unique hash of the input array using `wp_json_encode`.  This hash serves as the key for the cache.  Using a hash ensures fast lookups and avoids potential issues with complex array keys.

2. **Checking the Cache:** The code checks if the generated hash key exists in the `$sanitize_input_cache` static property. If found, the cached sanitized output is returned directly, bypassing the sanitization process.

3. **Caching the Result:**  If the hash is not found in the cache, the sanitization proceeds as before. After the sanitization is complete, the result is stored in the `$sanitize_input_cache`, associating it with the calculated hash key.

**Benefits of this Change:**

* **Performance Improvement:** By avoiding redundant calculations, this caching significantly improves performance, especially in scenarios where the same theme JSON data is sanitized repeatedly.
* **Reduced Resource Consumption:**  Less processing means reduced CPU load and memory usage.

**Potential Considerations:**

* **Cache Invalidation:** The current implementation doesn't have a mechanism for cache invalidation. This means that if the underlying theme JSON data changes, the cached value might become stale.  A more robust solution might consider ways to invalidate the cache when theme changes occur.
* **Memory Usage:** While generally beneficial, caching can consume memory.  If the number of unique theme JSON variations is extremely large, the cache could potentially grow quite large. Monitoring memory usage is advisable, especially in memory-constrained environments.

**Overall, this change is a positive improvement that addresses performance concerns in theme JSON sanitization.** The simple caching strategy effectively reduces redundant processing and enhances efficiency.  However, it's important to be aware of the potential need for cache invalidation in a production environment.

…l to `WP_Theme_JSON::reset_sanitize_input_cache()` before setting the transient containing global styles and settings.

This change likely addresses a caching issue where modifications to theme.json weren't being reflected because the sanitized input was cached. By resetting the sanitization cache before updating the transient,  the updated theme.json settings will be correctly sanitized and saved, ensuring the changes take effect.  This implies that prior to this change, the sanitized values were being retrieved from the cache, even if the theme.json file had been modified.  This fix ensures that the transient always contains the most up-to-date sanitized styles and settings.

Co-authored-by: Weston Ruter <[email protected]>

…_Theme_JSONsanitize

…JsonSanitize`.

Co-authored-by: Weston Ruter <[email protected]>

Co-authored-by: Weston Ruter <[email protected]>

…_Theme_JSONsanitize

adjuested cache key