refactor and simplify renderURLSearchParams & flattenObject

generator/template.go

@@ -196,78 +196,86 @@ function getNotifyEntityArrivalSink<T>(notifyCallback: NotifyStreamEntityArrival
   })
 }
 
+type RequestPayload = Record<string, unknown>;
+type Primitive = string | boolean | number;
+
+/**
+ * Checks if given value is of a primitive type
+ * @param  {unknown} value
+ * @return {boolean}
+ */
+function isPrimitive(value: unknown): boolean {
+  return (
+    typeof value === "string" ||
+    typeof value === "number" ||
+    typeof value === "boolean"
+  );
+}
+
 /**
- * Flattens a deeply nested object
- *
- * @param  {Object} deeplyNestedObject
+ * Flattens a deeply nested request payload and returns an object
+ * with only primitive values and non-empty array of primitive values
+ * @param  {RequestPayload} requestPayload
  * @param  {String} path
- * @return {Record<string, unknown>}
+ * @return {Record<string, Primitive | Array<Primitive>}
  */
-function flattenObject<T extends Record<string, unknown>>(
-  deeplyNestedObject: T,
+function flattenRequestPayload<T extends RequestPayload>(
+  requestPayload: T,
   path: string = ""
-): T {
-  return Object.keys(deeplyNestedObject).reduce(
+): Record<string, Primitive | Array<Primitive>> {
+  return Object.keys(requestPayload).reduce(
     (acc: T, key: string): T => {
-      const value = deeplyNestedObject[key];
-
-      const newPath = Array.isArray(deeplyNestedObject)
-        ? path + "." + key
-        : [path, key].filter(Boolean).join(".");
-      const isObject = [
-        typeof value === "object",
-        value !== null,
-        !(value instanceof Date),
-        !(value instanceof RegExp),
-        !(Array.isArray(value) && value.length === 0)
-      ].every(Boolean);
-
-      return isObject
-        ? { ...acc, ...flattenObject(value as Record<string, unknown>, newPath) }
-        : { ...acc, [newPath]: value };
+      const value = requestPayload[key];
+      const newPath = path ? [path, key].join(".") : key;
+
+      const isObject =
+        Object.prototype.toString.call(value) === "[object Object]";
+      const isNonEmptyPrimitiveArray =
+        Array.isArray(value) &&
+        value.every(v => isPrimitive(v)) &&
+        value.length > 0;
+
+      switch (true) {
+        case isObject:
+          acc = {
+            ...acc,
+            ...flattenRequestPayload(value as RequestPayload, newPath)
+          };
+          break;
+        case isPrimitive(value) || isNonEmptyPrimitiveArray:
+          acc = { ...acc, [newPath]: value };
+          break;
+      }
+
+      return acc;
     },
     {} as T
-  );
+  ) as Record<string, Primitive | Array<Primitive>>;
 }
 
 /**
- * Renders a deeply nested object into a string of URL search parameters
- * by first flattening the object and then removing non-primitive array keys,
- * non-primitive values and keys which are already present in the URL path.
- * @param  {Object} deeplyNestedObject
- * @param  {Array<string>} urlPathParams
- * @return {String}
+ * Renders a deeply nested request payload into a string of URL search
+ * parameters by first flattening the request payload and then removing keys
+ * which are already present in the URL path.
+ * @param  {RequestPayload} requestPayload
+ * @param  {string[]} urlPathParams
+ * @return {string}
  */
-export function renderURLSearchParams<T extends Record<string, unknown>>(
-  deeplyNestedObject: T,
+export function renderURLSearchParams<T extends RequestPayload>(
+  requestPayload: T,
   urlPathParams: string[] = []
 ): string {
-  const flattenedObject = flattenObject(deeplyNestedObject);
+  const flattenedRequestPayload = flattenRequestPayload(requestPayload);
 
-  const urlSearchParams = Object.keys(flattenedObject).reduce(
+  const urlSearchParams = Object.keys(flattenedRequestPayload).reduce(
     (acc: string[][], key: string): string[][] => {
-      const parts = key.split(".");
-      const index = parts.findIndex(f => Number(f) || f === "0");
-
-      // if key does not contain only one numeric index as the last element
-      // then it is an array of objects
-      if (parts.length === index + 1 || index === -1) {
-        // remove array index to render url search params properly
-        // according to http.proto
-        // https://github.com/googleapis/googleapis/blob/master/google/api/http.proto
-        const keyWithoutArrayIndex =
-          index > -1 ? parts.slice(0, index).join(".") : key;
-
-        // values should only be primitive types and key should not be
-        // present in the url path as a parameter
-        const value = flattenedObject[key];
-        if (
-          (typeof value === "string" ||
-            typeof value === "boolean" ||
-            typeof value === "number") &&
-          !urlPathParams.find(f => f === key)
-        ) {
-          acc = [...acc, [keyWithoutArrayIndex, value.toString()]];
+      // key should not be present in the url path as a parameter
+      const value = flattenedRequestPayload[key];
+      if (!urlPathParams.find(f => f === key)) {
+        if (Array.isArray(value)) {
+          acc = [...acc, ...value.map(m => [key, m.toString()])];
+        } else {
+          acc = [...acc, [key, value.toString()]];
         }
       }
 
@@ -276,9 +284,7 @@ export function renderURLSearchParams<T extends Record<string, unknown>>(
     [] as string[][]
   );
 
-  return urlSearchParams.length > 0
-    ? "?" + new URLSearchParams(urlSearchParams).toString()
-    : "";
+  return "?" + new URLSearchParams(urlSearchParams).toString();
 }
 `
 
@@ -317,21 +323,21 @@ func renderURL(r *registry.Registry) func(method data.Method) string {
 		url := method.URL
 		reg := regexp.MustCompile("{([^}]+)}")
 		matches := reg.FindAllStringSubmatch(url, -1)
-		fieldList := "["
+		fieldsInPath := "["
 		if len(matches) > 0 {
 			log.Debugf("url matches %v", matches)
 			for _, m := range matches {
 				expToReplace := m[0]
 				fieldName := fieldNameFn(m[1])
 				part := fmt.Sprintf(`${req["%s"]}`, fieldName)
 				url = strings.ReplaceAll(url, expToReplace, part)
-				fieldList += fmt.Sprintf(`"%s", `, fieldName)
+				fieldsInPath += fmt.Sprintf(`"%s", `, fieldName)
 			}
 		}
-		fieldList = strings.TrimRight(fieldList, ", ") + "]"
+		fieldsInPath = strings.TrimRight(fieldsInPath, ", ") + "]"
 
 		if !method.ClientStreaming && method.HTTPMethod == "GET" {
-			url += fmt.Sprintf("${fm.renderURLSearchParams(req, %s)}", fieldList)
+			url += fmt.Sprintf("${fm.renderURLSearchParams(req, %s)}", fieldsInPath)
 		}
 
 		return url