Add check for onChange function

src/XmlScope.spec.ts

@@ -103,6 +103,7 @@ describe('XmlScope', () => {
                         <function id="func3" />
                         <function name="" />
                         <function name />
+                        <field id="field1" type="string" onChange="func4" />
                     </interface>
                     <script uri="child.brs"/>
                 </component>
@@ -127,6 +128,9 @@ describe('XmlScope', () => {
                 range: Range.create(7, 9, 7, 17)
             }, { // syntax error expecting '=' but found '/>'
                 code: DiagnosticMessages.xmlGenericParseError('').code
+            }, { // onChange function
+                ...DiagnosticMessages.xmlFunctionNotFound('func4'),
+                range: Range.create(8, 51, 8, 56)
             }]);
         });
 

src/XmlScope.ts

@@ -71,7 +71,7 @@ export class XmlScope extends Scope {
         }
         //validate fields
         for (const field of api.fields) {
-            const { id, type } = field;
+            const { id, type, onChange } = field;
             if (!id) {
                 this.diagnosticMissingAttribute(field, 'id');
             }
@@ -86,6 +86,15 @@ export class XmlScope extends Scope {
                     file: this.xmlFile
                 });
             }
+            if (onChange) {
+                if (!callableContainerMap.has(onChange.toLowerCase())) {
+                    this.diagnostics.push({
+                        ...DiagnosticMessages.xmlFunctionNotFound(onChange),
+                        range: field.getAttribute('onchange').value.range,
+                        file: this.xmlFile
+                    });
+                }
+            }
         }
     }
 

src/parser/SGTypes.ts

@@ -39,7 +39,7 @@ export class SGTag {
     }
 
     getAttributeValue(name: string): string | undefined {
-        return this.getAttribute(name)?.value?.text;
+        return this.getAttribute(name.toLowerCase())?.value?.text;
     }
 
     setAttribute(name: string, value: string) {