Fixed bug with default values for constructor parameters

Perryvw · Perryvw · commit 6c6af51354ca · 2018-11-18T20:49:44.000+01:00
diff --git a/src/Transpiler.ts b/src/Transpiler.ts
@@ -1889,29 +1889,30 @@ export abstract class LuaTranspiler {
 
     public transpileConstructor(node: ts.ConstructorDeclaration,
                                 className: string): string {
-        const extraInstanceFields = [];
+        // Check for field declarations in constructor
+        const constructorFieldsDeclarations = node.parameters.filter(p => p.modifiers !== undefined);
 
-        const parameters = ["self"];
-        node.parameters.forEach(param => {
-            // If param has decorators, add extra instance field
-            if (param.modifiers !== undefined) {
-                extraInstanceFields.push(this.transpileIdentifier(param.name as ts.Identifier));
-            }
-            // Add to parameter list
-            parameters.push(this.transpileIdentifier(param.name as ts.Identifier));
-        });
-
-        let result = this.indent + `function ${className}.constructor(${parameters.join(",")})\n`;
+        const [paramNames, spreadIdentifier] = this.transpileParameters(node.parameters);
 
-        // Add in instance field declarations
-        for (const f of extraInstanceFields) {
-            result += this.indent + `    self.${f} = ${f}\n`;
-        }
+        let result = this.indent + `function ${className}.constructor(${["self"].concat(paramNames).join(",")})\n`;
 
         // Transpile constructor body
         this.pushIndent();
         this.classStack.push(className);
-        result += this.transpileBlock(node.body);
+
+        // Add in instance field declarations
+        for (const declaration of constructorFieldsDeclarations) {
+            const declarationName = this.transpileIdentifier(declaration.name as ts.Identifier);
+            if (declaration.initializer) {
+                const value = this.transpileExpression(declaration.initializer);
+                result += this.indent + `self.${declarationName} = ${declarationName} or ${value}\n`;
+            } else {
+                result += this.indent + `self.${declarationName} = ${declarationName}\n`;
+            }
+        }
+
+        result += this.transpileFunctionBody(node.parameters, node.body, spreadIdentifier);
+
         this.classStack.pop();
         this.popIndent();
 
diff --git a/test/unit/class.spec.ts b/test/unit/class.spec.ts
@@ -44,7 +44,7 @@ export class ClassTests {
 
     @Test("ClassConstructorAssignment")
     public classConstructorAssignment(): void {
-         // Transpile
+        // Transpile
         const lua = util.transpileString(
             `class a { constructor(public field: number) {} }
             return new a(4).field;`
@@ -57,6 +57,26 @@ export class ClassTests {
         Expect(result).toBe(4);
     }
 
+    @Test("ClassConstructorDefaultParameter")
+    public classConstructorDefaultParameter(): void {
+        const result = util.transpileAndExecute(
+            `class a { public field: number; constructor(f: number = 3) { this.field = f; } }
+            return new a().field;`
+        );
+
+        Expect(result).toBe(3);
+    }
+
+    @Test("ClassConstructorAssignmentDefault")
+    public classConstructorAssignmentParameterDefault(): void {
+        const result = util.transpileAndExecute(
+            `class a { constructor(public field: number = 3) { } }
+            return new a().field;`
+        );
+
+        Expect(result).toBe(3);
+    }
+
     @Test("ClassNewNoBrackets")
     public classNewNoBrackets(): void {
         // Transpile
