Flow opaque type 6.x backport (#6081)

* Flow opaque type backport

* Add tests for strip types, comments, and babel-generator

* Fix failing tests, run scripts

* Bump babylon to 6.18.0

Author: jbrown215

lib/types.js

@@ -35,7 +35,7 @@
     "babel-register": "^6.24.1",
     "babel-traverse": "^6.25.0",
     "babel-types": "^6.25.0",
-    "babylon": "^6.17.2",
+    "babylon": "^6.18.0",
     "convert-source-map": "^1.1.0",
     "debug": "^2.1.1",
     "json5": "^0.5.0",

packages/babel-core/package.json

@@ -22,6 +22,6 @@
   },
   "devDependencies": {
     "babel-helper-fixtures": "^6.22.0",
-    "babylon": "^6.17.2"
+    "babylon": "^6.18.0"
   }
 }

packages/babel-generator/package.json

@@ -1,3 +1,5 @@
+import * as t from "babel-types";
+
 export function AnyTypeAnnotation() {
   this.word("any");
 }
@@ -20,17 +22,21 @@ export function NullLiteralTypeAnnotation() {
   this.word("null");
 }
 
-export function DeclareClass(node: Object) {
-  this.word("declare");
-  this.space();
+export function DeclareClass(node: Object, parent: Object) {
+  if (!t.isDeclareExportDeclaration(parent)) {
+    this.word("declare");
+    this.space();
+  }
   this.word("class");
   this.space();
   this._interfaceish(node);
 }
 
-export function DeclareFunction(node: Object) {
-  this.word("declare");
-  this.space();
+export function DeclareFunction(node: Object, parent: Object) {
+  if (!t.isDeclareExportDeclaration(parent)) {
+    this.word("declare");
+    this.space();
+  }
   this.word("function");
   this.space();
   this.print(node.id, node);
@@ -69,16 +75,64 @@ export function DeclareTypeAlias(node: Object) {
   this.TypeAlias(node);
 }
 
-export function DeclareVariable(node: Object) {
-  this.word("declare");
-  this.space();
+export function DeclareOpaqueType(node: Object, parent: Object) {
+  if (!t.isDeclareExportDeclaration(parent)) {
+    this.word("declare");
+    this.space();
+  }
+  this.OpaqueType(node);
+}
+
+export function DeclareVariable(node: Object, parent: Object) {
+  if (!t.isDeclareExportDeclaration(parent)) {
+    this.word("declare");
+    this.space();
+  }
   this.word("var");
   this.space();
   this.print(node.id, node);
   this.print(node.id.typeAnnotation, node);
   this.semicolon();
 }
 
+export function DeclareExportDeclaration(node: Object) {
+  this.word("declare");
+  this.space();
+  this.word("export");
+  this.space();
+  if (node.default) {
+    this.word("default");
+    this.space();
+  }
+
+  FlowExportDeclaration.apply(this, arguments);
+}
+
+function FlowExportDeclaration(node: Object) {
+  if (node.declaration) {
+    const declar = node.declaration;
+    this.print(declar, node);
+    if (!t.isStatement(declar)) this.semicolon();
+  } else {
+    this.token("{");
+    if (node.specifiers.length) {
+      this.space();
+      this.printList(node.specifiers, node);
+      this.space();
+    }
+    this.token("}");
+
+    if (node.source) {
+      this.space();
+      this.word("from");
+      this.space();
+      this.print(node.source, node);
+    }
+
+    this.semicolon();
+  }
+}
+
 export function ExistentialTypeParam() {
   this.token("*");
 }
@@ -222,6 +276,26 @@ export function TypeAlias(node: Object) {
   this.print(node.right, node);
   this.semicolon();
 }
+export function OpaqueType(node: Object) {
+  this.word("opaque");
+  this.space();
+  this.word("type");
+  this.space();
+  this.print(node.id, node);
+  this.print(node.typeParameters, node);
+  if (node.supertype) {
+    this.token(":");
+    this.space();
+    this.print(node.supertype, node);
+  }
+  if (node.impltype) {
+    this.space();
+    this.token("=");
+    this.space();
+    this.print(node.impltype, node);
+  }
+  this.semicolon();
+}
 
 export function TypeAnnotation(node: Object) {
   this.token(":");

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

@@ -18,3 +18,7 @@ declare type B = {
 declare interface I { foo: string }
 declare interface I<T> { foo: T }
 declare module.exports: { foo: string }
+declare opaque type Foo<T>: Bar<T>;
+declare opaque type ID;
+declare opaque type num: number;
+declare opaque type NumArray;

packages/babel-generator/test/fixtures/flow/declare-statements/actual.js

@@ -18,3 +18,7 @@ declare type B = {
 declare interface I { foo: string }
 declare interface I<T> { foo: T }
 declare module.exports: { foo: string }
+declare opaque type Foo<T>: Bar<T>;
+declare opaque type ID;
+declare opaque type num: number;
+declare opaque type NumArray;

packages/babel-generator/test/fixtures/flow/declare-statements/expected.js

@@ -0,0 +1,14 @@
+opaque type ID = string;
+opaque type Foo<T> = Bar<T>;
+opaque type Maybe<T> = _Maybe<T, *>;
+export opaque type Foo = number;
+
+opaque type union =
+ | {type: "A"}
+ | {type: "B"}
+;
+
+opaque type overloads =
+  & ((x: string) => number)
+  & ((x: number) => string)
+;

packages/babel-generator/test/fixtures/flow/opaque-type-alias/actual.js

@@ -0,0 +1,8 @@
+opaque type ID = string;
+opaque type Foo<T> = Bar<T>;
+opaque type Maybe<T> = _Maybe<T, *>;
+export opaque type Foo = number;
+
+opaque type union = { type: "A" } | { type: "B" };
+
+opaque type overloads = (x: string) => number & (x: number) => string;

packages/babel-generator/test/fixtures/flow/opaque-type-alias/expected.js

@@ -0,0 +1,15 @@
+function a() {}
+opaque type A = number;
+opaque type B = {
+  name: string;
+};
+
+opaque type union =
+ | {type: "A"}
+ | {type: "B"}
+;
+
+opaque type overloads =
+  & ((x: string) => number)
+  & ((x: number) => string)
+;

packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/opaque-type-alias/actual.js

@@ -0,0 +1,13 @@
+function a() {}
+/*:: opaque type A = number;*/
+/*:: opaque type B = {
+  name: string;
+};*/
+/*:: opaque type union =
+ | {type: "A"}
+ | {type: "B"}
+;*/
+/*:: opaque type overloads =
+  & ((x: string) => number)
+  & ((x: number) => string)
+;*/