[ui5-builder][INTERNAL] Async bundling for require section (#1048)

Require's section `async` flag has different default values based on the
specVersion. However, async require is now build by default.
We need to explicitly default `async=false` for specVersions lower than
4.0

---------

Co-authored-by: Günter Klatt <57760635+KlattG@users.noreply.github.com>
Co-authored-by: Matthias Oßwald <mat.osswald@sap.com>

Author: 3 people

packages/builder/lib/processors/bundlers/moduleBundler.js

@@ -33,10 +33,10 @@ const log = getLogger("builder:processors:bundlers:moduleBundler");
  *      the ui5loader is available.
  *	</li>
  *	<li>
- *		<code>require</code>: A 'require' section is transformed into a sequence of jQuery.sap.require calls. The
- *		list will be resolved like an include pattern list in any of the other sections and for each of the resolved
- *		modules, a jQuery.sap.require will be created. In case the ui5loader is available, 'sap.ui.requireSync' is
- *		used instead.
+ *		<code>require</code>: A `require` section is transformed into a `sap.ui.require` call with all the dependencies
+ *		resolved. This module comes with an `async` flag. When set to false, the modules
+ *		are loaded using `sap.ui.requireSync` instead of `sap.ui.require`.
+ *		**Note:** The `sap.ui.requireSync` API is not available in UI5 version 2.x.
  *	</li>
  *	<li>
  *		<code>bundleInfo</code>: A 'bundleInfo' section describes the content of another named bundle. This information
@@ -75,6 +75,11 @@ const log = getLogger("builder:processors:bundlers:moduleBundler");
  * @property {boolean} [declareRawModules=false] Whether raw modules should be declared after jQuery.sap.global
  *		became available. With the usage of the ui5loader, this flag should be set to 'false'
  * @property {boolean} [sort=true] Whether the modules should be sorted by their dependencies
+ * @property {boolean} [async=true] Whether the `require` section of the module should be loaded asynchronously.
+ * 		When set to true, the modules are loaded using a single `sap.ui.require` call instead of multiple
+ *      `sap.ui.requireSync` calls.
+ * 		The latter API is not available in UI5 version 2.x.
+ * 		**Note:** This property is available only for `mode=require`.
  */
 
 /* eslint-disable max-len */

packages/builder/lib/tasks/bundlers/utils/applyDefaultsToBundleDefinition.js

@@ -20,8 +20,12 @@ export function applyDefaultsToBundleDefinition(bundleDefinition, taskUtil) {
 		// Since specVersion: 4.0 "require" section starts loading asynchronously.
 		// If specVersion cannot be determined, the latest spec is taken into account.
 		// This is a breaking change in specVersion: 4.0
-		if (section.mode === "require" && (!taskUtil || taskUtil.getProject().getSpecVersion().gte("4.0"))) {
-			defaultValues.async = true;
+		if (section.mode === "require") {
+			// Builder.js already treats missing async flag as truthy value and builds asynchronously by default
+
+			if (taskUtil && taskUtil.getProject().getSpecVersion().lt("4.0")) {
+				defaultValues.async = false;
+			}
 		}
 
 		return Object.assign(defaultValues, section);