Fix: handle nullish values in template sinks with ?? operator

src/parser/parser.test.ts

@@ -588,5 +588,20 @@ describe('Parser', () => {
 	});
 
 	describe('Plain Objects', () => {
-	});
+    describe('Content', () => {
+        it('renders 0 when an object has a .value of 0', () => {
+            const zeroValueObject = { value: 0 };
+            const template = rml`<div>${zeroValueObject}</div>`;
+            expect(template).toEqual('<div>0</div>');
+        });
+    });
+
+    describe('Attributes', () => { 
+        it('renders 0 in an attribute when an object has a .value of 0', () => {
+            const zeroValueObject = { value: 0 };
+            const template = rml`<input value="${zeroValueObject}">`;
+            expect(template).toEqual(`<input value="0">`);
+        });
+    });
+});
 });

src/parser/parser.ts

@@ -169,7 +169,22 @@ export function rml(strings: TemplateStringsArray, ...expressions: RMLTemplateEx
 				acc = accPlusString +expression.join('');
 			} else {
 				// expression is a future or an object
-
+
+                if (
+                    expression &&
+                    typeof expression === 'object' &&
+                    'value' in expression &&
+                    !isPromise(expression) &&
+                    !isObservable(expression)
+                ) {
+                    const valueType = typeof expression.value;
+                    if (['string', 'number', 'boolean'].includes(valueType)) {
+                        acc = accPlusString + (expression.value ?? '');
+                        continue;
+                    }
+                }
+            				}
+				// Future / Object Sink
 				const nextString = strings[i+1];
 				// if it's a BehaviorSubject or any other sync stream (e.g.: startWith operator), pick its initial/current value to render it synchronously
 				const initialValue = currentValue(expression.source ?? expression);
@@ -268,7 +283,7 @@ export function rml(strings: TemplateStringsArray, ...expressions: RMLTemplateEx
 					addRef(ref, isSinkBindingConfiguration(_source) ? _source : InnerHTML(_source));
 					acc = acc
 						+(existingRef ? string : string.replace(/\s*>\s*$/, ` ${RESOLVE_ATTRIBUTE}="${ref}">`))
-						+(initialValue || '')
+						+(initialValue ?? '')
 					;
 
 				} else if(/>?\s*[^<]*$/m.test(string) && /^\s*[^<]*\s*<?/m.test(nextString)) {