fix: typeArguments on decorator structure should output type arguments

Ref #1205

Author: dsherret

packages/ts-morph/src/structurePrinters/decorator/DecoratorStructurePrinter.ts

@@ -13,10 +13,23 @@ export class DecoratorStructurePrinter extends NodePrinter<OptionalKind<Decorato
 
     protected printTextInternal(writer: CodeBlockWriter, structure: OptionalKind<DecoratorStructure>) {
         writer.write(`@${structure.name}`);
+        this.printTypeArguments(writer, structure);
         this.printArguments(writer, structure);
     }
 
-    printArguments(writer: CodeBlockWriter, structure: OptionalKind<DecoratorStructure>) {
+    private printTypeArguments(writer: CodeBlockWriter, structure: OptionalKind<DecoratorStructure>) {
+        if (structure.typeArguments == null || structure.typeArguments.length === 0)
+            return;
+
+        writer.write("<");
+        for (let i = 0; i < structure.typeArguments.length; i++) {
+            writer.conditionalWrite(i > 0, ", ");
+            writer.write(this.getTextWithQueuedChildIndentation(writer, structure.typeArguments[i]));
+        }
+        writer.write(">");
+    }
+
+    private printArguments(writer: CodeBlockWriter, structure: OptionalKind<DecoratorStructure>) {
         if (structure.arguments == null)
             return;
 

packages/ts-morph/src/tests/structurePrinters/decorator/decoratorStructurePrinterTests.ts

@@ -27,5 +27,19 @@ describe(nameof(DecoratorStructurePrinter), () => {
                 doTest({ name: "dec", arguments: writer => writer.writeLine("1,").write("2") }, `@dec(1,\n    2)`);
             });
         });
+
+        describe("type arguments", () => {
+            it("should not write when empty", () => {
+                doTest({ name: "dec", typeArguments: [] }, `@dec`);
+            });
+
+            it("should write", () => {
+                doTest({ name: "dec", typeArguments: ["string"], arguments: ["1"] }, `@dec<string>(1)`);
+            });
+
+            it("should write multiple", () => {
+                doTest({ name: "dec", typeArguments: ["string", "number"] }, `@dec<string, number>`);
+            });
+        });
     });
 });