Port flow object spread from #418 to 6.x (#5653)

* Add support for object type spread

* Type spread: remove variance and add stripping test

* Fix tests

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

@@ -333,6 +333,11 @@ export function ObjectTypeProperty(node: Object) {
   this.print(node.value, node);
 }
 
+export function ObjectTypeSpreadProperty(node: Object) {
+  this.token("...");
+  this.print(node.argument, node);
+}
+
 export function QualifiedTypeIdentifier(node: Object) {
   this.print(node.qualification, node);
   this.token(".");

packages/babel-generator/test/fixtures/flow/object-literal-types/actual.js

@@ -0,0 +1,7 @@
+type U = {};
+type V = {};
+type T = { ...U, };
+type T = { ...U, ...V };
+type T = { p: V, ...U };
+type T = { ...U, p: V, };
+type T = { ...{}|{ p: V, }};

packages/babel-generator/test/fixtures/flow/object-literal-types/expected.js

@@ -0,0 +1,7 @@
+type U = {};
+type V = {};
+type T = { ...U };
+type T = { ...U; ...V; };
+type T = { p: V; ...U; };
+type T = { ...U; p: V; };
+type T = { ...{} | { p: V } };

packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-type-annotations/actual.js

@@ -44,6 +44,7 @@ var a: { subObj: {strVal: string} }
 var a: { subObj: ?{strVal: string} }
 var a: { param1: number; param2: string }
 var a: { param1: number; param2?: string }
+var a: { ...any; ...{}|{p: void} };
 var a: { [a: number]: string; [b: number]: string; };
 var a: { add(x: number, ...y: Array<string>): void };
 var a: { id<T>(x: T): T; };

packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-type-annotations/expected.js

@@ -47,6 +47,7 @@ var a;
 var a;
 var a;
 var a;
+var a;
 var a = [1, 2, 3];
 a = class Foo {};
 a = class Foo extends Bar {};

packages/babel-types/src/definitions/flow.js

@@ -308,6 +308,14 @@ defineType("ObjectTypeProperty", {
   }
 });
 
+defineType("ObjectTypeSpreadProperty", {
+  visitor: ["argument"],
+  aliases: ["Flow", "UserWhitespacable"],
+  fields: {
+    // todo
+  },
+});
+
 defineType("QualifiedTypeIdentifier", {
   visitor: ["id", "qualification"],
   aliases: ["Flow"],