When handling potentially null values from functions like `tryParse()` or `tryCast()`, avoid the pattern of checking for null/none and then immediately using `KJ_ASSERT_NONNULL` or `JSG_REQUIRE_NONNULL`. This creates redundant checks that make code harder to read and understand. Instead, use the `KJ_UNWRAP_OR` macro to handle the null case directly and extract the value in one step. This pattern is cleaner, more efficient, and eliminates the cognitive overhead of tracking whether a value can be null. **Problematic pattern:** ```cpp auto currentUrl = jsg::Url::tryParse(base.asPtr()); if (currentUrl == kj::none) { auto exception = JSG_KJ_EXCEPTION(FAILED, TypeError, "Invalid current URL"); return js.rejectedPromise>(kj::mv(exception)); } // Later: KJ_ASSERT_NONNULL(currentUrl) - redundant since we already checked ``` **Preferred pattern:** ```cpp auto currentUrl = KJ_UNWRAP_OR(jsg::Url::tryParse(base.asPtr()), { auto exception = JSG_KJ_EXCEPTION(FAILED, TypeError, "Invalid current URL"); return js.rejectedPromise>(kj::mv(exception)); }); // Now currentUrl can be used directly without null checks ``` This approach makes the code more readable by eliminating the need to verify that null checks guarantee non-null values later in the code.