fix: remove custom "falsy" checks from ifDefined (#544)

- all string attributes with an empty string value will now be written in the DOM

FIXES: #542

Author: MapTo0

packages/base/src/renderer/ifDefined.js

@@ -8,7 +8,7 @@ import {
 	lit-html directive that removes and attribute if it is undefined
 */
 export default directive(value => part => {
-	if ((value === undefined || value === null || value === "") && part instanceof AttributePart) {
+	if ((value === undefined) && part instanceof AttributePart) {
 		if (value !== part.value) {
 			const name = part.committer.name;
 			part.committer.element.removeAttribute(name);

packages/main/src/Link.hbs

@@ -1,7 +1,7 @@
 <a
 	class="{{classes.main}}"
 	role="link"
-	href="{{href}}"
+	href="{{parsedRef}}"
 	target="{{target}}"
 	rel="{{_rel}}"
 	tabindex="{{tabIndex}}"

packages/main/src/Link.js

@@ -263,6 +263,10 @@ class Link extends UI5Element {
 			},
 		};
 	}
+
+	get parsedRef() {
+		return this.href.length > 0 ? this.href : undefined;
+	}
 }
 
 Bootstrap.boot().then(_ => {