Fix typescript generator params (#9524)

* Fix typescript generator params

* add TSOptionalType, TSRestType, add more test

packages/babel-generator/src/generators/typescript.js

@@ -231,7 +231,7 @@ export function tsPrintBraced(members, node) {
 }
 
 export function TSArrayType(node) {
-  this.print(node.elementType);
+  this.print(node.elementType, node);
   this.token("[]");
 }
 

packages/babel-generator/src/node/parentheses.js

@@ -136,6 +136,18 @@ export function TSTypeAssertion() {
   return true;
 }
 
+export function TSUnionType(node: Object, parent: Object): boolean {
+  return (
+    t.isTSArrayType(parent) ||
+    t.isTSOptionalType(parent) ||
+    t.isTSIntersectionType(parent) ||
+    t.isTSUnionType(parent) ||
+    t.isTSRestType(parent)
+  );
+}
+
+export { TSUnionType as TSIntersectionType };
+
 export function BinaryExpression(node: Object, parent: Object): boolean {
   // let i = (1 in []);
   // for ((1 in []);;);

packages/babel-generator/test/fixtures/typescript/types-union-intersection/output.js

@@ -1,4 +1,4 @@
 let union: number | null | undefined;
 let intersection: number & string;
-let precedence1: number | string & boolean;
+let precedence1: number | (string & boolean);
-let precedence2: number & string | boolean;
+let precedence2: (number & string) | boolean;

packages/babel-generator/test/index.js

@@ -426,6 +426,40 @@ describe("programmatic generation", function() {
       }).toThrow();
     });
   });
+
+  describe("typescript generate parantheses if necessary", function() {
+    it("wraps around union for array", () => {
+      const typeStatement = t.TSArrayType(
+        t.TSUnionType([
+          t.TSIntersectionType([t.TSNumberKeyword(), t.TSBooleanKeyword()]),
+          t.TSNullKeyword(),
+        ]),
+      );
+      const output = generate(typeStatement).code;
+      expect(output).toBe("((number & boolean) | null)[]");
+    });
+    it("wraps around intersection for array", () => {
+      const typeStatement = t.TSArrayType(
+        t.TSIntersectionType([t.TSNumberKeyword(), t.TSBooleanKeyword()]),
+      );
+      const output = generate(typeStatement).code;
+      expect(output).toBe("(number & boolean)[]");
+    });
+    it("wraps around rest", () => {
+      const typeStatement = t.tsRestType(
+        t.TSIntersectionType([t.TSNumberKeyword(), t.TSBooleanKeyword()]),
+      );
+      const output = generate(typeStatement).code;
+      expect(output).toBe("...(number & boolean)");
+    });
+    it("wraps around optional type", () => {
+      const typeStatement = t.tsOptionalType(
+        t.TSIntersectionType([t.TSNumberKeyword(), t.TSBooleanKeyword()]),
+      );
+      const output = generate(typeStatement).code;
+      expect(output).toBe("(number & boolean)?");
+    });
+  });
 });
 
 describe("CodeGenerator", function() {