Add a documentation for the useFlowNavigator hook

client/landing/stepper/declarative-flow/migration/hooks/use-flow-navigator.ts

@@ -8,14 +8,52 @@ interface Options {
 	persistedUrlParams: string[];
 }
 
+/**
+ * Custom hook for managing navigation within a flow, handling query parameters and step transitions.
+ * @param {Object} options - Configuration options for the hook.
+ * @param {Navigate<StepperStep[]>} options.navigate - Function to navigate between steps.
+ * @param {string[]} options.persistedUrlParams - Array of URL parameter keys to persist across navigation.
+ * @returns {Object} An object containing utility functions for flow navigation.
+ * @returns {Function} .getFromPropsOrUrl - Retrieves a value from props or URL query parameters.
+ * @returns {Function} .navigateWithQueryParams - Navigates to a step while managing query parameters.
+ * @example
+ * const { navigateWithQueryParams, getFromPropsOrUrl } = useFlowNavigator({
+ *   navigate: stepNavigationFunction,
+ *   persistedUrlParams: ['siteId', 'plan']
+ * });
+ */
+
 export const useFlowNavigator = ( { navigate, persistedUrlParams }: Options ) => {
 	const [ query ] = useSearchParams();
 
+	/**
+	 * Retrieves a value from either the provided props or the current URL query parameters.
+	 * @param {string} key - The key to look for in props or URL query parameters.
+	 * @param {ProvidedDependencies} [props] - Optional object containing provided dependencies.
+	 * @returns {Primitive | undefined} The value associated with the key, or undefined if not found or if the value is an object.
+	 *
+	 * This function first checks if the key exists in the provided props. If not found or if props are not provided,
+	 * it then looks for the key in the current URL query parameters. If the value is found but is an object,
+	 * the function returns undefined. This ensures that only primitive values are returned.
+	 */
 	const getFromPropsOrUrl = ( key: string, props?: ProvidedDependencies ): Primitive => {
 		const value = props?.[ key ] || query.get( key );
 		return typeof value === 'object' ? undefined : ( value as Primitive );
 	};
 
+	/**
+	 * Navigates to a specified step while preserving and updating query parameters.
+	 * @param {StepperStep} step - The step to navigate to.
+	 * @param {string[]} [keys] - Additional query parameter keys to include.
+	 * @param {ProvidedDependencies} [props] - Additional properties to consider for query params.
+	 * @param {Object} [options] - Navigation options.
+	 * @param {boolean} options.replaceHistory - If true, replaces the current history entry instead of adding a new one.
+	 * @returns {void}
+	 *
+	 * This function combines persisted URL parameters with additional specified keys,
+	 * retrieves their values from either props or the current URL, and navigates to
+	 * the given step with these parameters included in the URL.
+	 */
 	const navigateWithQueryParams = (
 		step: StepperStep,
 		keys: string[] = [],