feat(decorators): inline more types of decorators (#1864)

src/printer.js

@@ -92,10 +92,18 @@ function genericPrint(path, options, printPath, args) {
         prefix = "";
       }
 
+      // #1817
       if (
         node.decorators.length === 1 &&
+        node.type !== "ClassDeclaration" &&
+        node.type !== "MethodDefinition" &&
         (decorator.type === "Identifier" ||
-          decorator.type === "MemberExpression")
+          decorator.type === "MemberExpression" ||
+          (decorator.type === "CallExpression" &&
+            decorator.arguments.length === 1 &&
+            (isStringLiteral(decorator.arguments[0]) ||
+              decorator.arguments[0].type === "Identifier" ||
+              decorator.arguments[0].type === "MemberExpression")))
       ) {
         separator = " ";
       }

tests/decorators/__snapshots__/jsfmt.spec.js.snap

@@ -45,7 +45,8 @@ import {observable} from "mobx";
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 import { observable } from "mobx";
 
-@observer class OrderLine {
+@observer
+class OrderLine {
   @observable price: number = 0;
   @observable amount: number = 1;
 

tests/typescript_decorators/__snapshots__/jsfmt.spec.js.snap

@@ -20,3 +20,101 @@ export class TestTextFileService {
 export class TabCompletionController {}
 
 `;
+
+exports[`inline-decorators.ts 1`] = `
+
+@d1
+@d2(foo)
+@d3.bar
+@d4.baz()
+class Class1 {}
+
+class Class2 {
+    @d1
+    @d2(foo)
+    @d3.bar
+    @d4.baz()
+    method1() {}
+
+    @d1
+    method2() {}
+
+    @d2(foo)
+    method3() {}
+
+    @d3.bar
+    method4() {}
+}
+
+class Class3 {
+    @d1 fieldA;
+    @d2(foo) fieldB;
+    @d3.bar fieldC;
+    @d4.baz() fieldD;
+
+    constructor (
+        @d1 private x: number,
+        @d2(foo) private y: number,
+        @d3('foo') private z: number,
+        @d4({
+            x: string
+        }) private a: string,
+    ) {}
+}
+
+@decorated class Foo {}
+
+class Bar {
+    @decorated method() {}
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+@d1
+@d2(foo)
+@d3.bar
+@d4.baz()
+class Class1 {}
+
+class Class2 {
+  @d1
+  @d2(foo)
+  @d3.bar
+  @d4.baz()
+  method1() {}
+
+  @d1
+  method2() {}
+
+  @d2(foo)
+  method3() {}
+
+  @d3.bar
+  method4() {}
+}
+
+class Class3 {
+  @d1 fieldA;
+  @d2(foo) fieldB;
+  @d3.bar fieldC;
+  @d4.baz()
+  fieldD;
+
+  constructor(
+    @d1 private x: number,
+    @d2(foo) private y: number,
+    @d3("foo") private z: number,
+    @d4({
+      x: string
+    })
+    private a: string
+  ) {}
+}
+
+@decorated
+class Foo {}
+
+class Bar {
+  @decorated
+  method() {}
+}
+
+`;

tests/typescript_decorators/inline-decorators.ts

@@ -0,0 +1,45 @@
+
+@d1
+@d2(foo)
+@d3.bar
+@d4.baz()
+class Class1 {}
+
+class Class2 {
+    @d1
+    @d2(foo)
+    @d3.bar
+    @d4.baz()
+    method1() {}
+
+    @d1
+    method2() {}
+
+    @d2(foo)
+    method3() {}
+
+    @d3.bar
+    method4() {}
+}
+
+class Class3 {
+    @d1 fieldA;
+    @d2(foo) fieldB;
+    @d3.bar fieldC;
+    @d4.baz() fieldD;
+
+    constructor (
+        @d1 private x: number,
+        @d2(foo) private y: number,
+        @d3('foo') private z: number,
+        @d4({
+            x: string
+        }) private a: string,
+    ) {}
+}
+
+@decorated class Foo {}
+
+class Bar {
+    @decorated method() {}
+}