perf(core): make classDeclaration validation more CPU efficient (#582)

Signed-off-by: Matt Roberts <[email protected]>

packages/concerto-core/lib/introspect/classdeclaration.js

@@ -212,16 +212,12 @@ class ClassDeclaration extends Decorated {
         super.validate();
 
         const declarations = this.getModelFile().getAllDeclarations();
-        for (let n = 0; n < declarations.length; n++) {
-            let declaration = declarations[n];
-
-            // check we don't have an asset with the same name
-            for (let i = n + 1; i < declarations.length; i++) {
-                let otherDeclaration = declarations[i];
-                if (declaration.getFullyQualifiedName() === otherDeclaration.getFullyQualifiedName()) {
-                    throw new IllegalModelException(`Duplicate class name ${declaration.getName()}`);
-                }
-            }
+        const declarationNames = declarations.map(d => d.getFullyQualifiedName());
+        const uniqueNames = [...new Set(declarationNames)];
+
+        if (uniqueNames.length !== declarationNames.length) {
+            const duplicateElements = declarationNames.filter((item, index) => declarationNames.indexOf(item) !== index);
+            throw new IllegalModelException(`Duplicate class name ${duplicateElements[0]}`);
         }
 
         // if we have a super type make sure it exists