Add "decoratorsLegacy" to presets

packages/babel-preset-stage-0/README.md

@@ -47,3 +47,9 @@ Enable "loose" transformations for any plugins in this preset that allow them.
 `boolean`, defaults to `false`.
 
 Will use the native built-in instead of trying to polyfill behavior for any plugins that require one.
+
+### `decoratorsLegacy`
+
+`boolean`, defaults to `false`.
+
+Use the legacy (stage 1) decorators syntax and behavior.

packages/babel-preset-stage-0/src/index.js

@@ -3,16 +3,10 @@ import presetStage1 from "@babel/preset-stage-1";
 
 import transformFunctionBind from "@babel/plugin-proposal-function-bind";
 
-export default declare((api, opts) => {
+export default declare((api, opts = {}) => {
   api.assertVersion(7);
 
-  let loose = false;
+  const { loose = false, useBuiltIns = false, decoratorsLegacy = false } = opts;
-  let useBuiltIns = false;
-
-  if (opts !== undefined) {
-    if (opts.loose !== undefined) loose = opts.loose;
-    if (opts.useBuiltIns !== undefined) useBuiltIns = opts.useBuiltIns;
-  }
 
   if (typeof loose !== "boolean") {
     throw new Error("@babel/preset-stage-0 'loose' option must be a boolean.");
@@ -22,9 +16,22 @@ export default declare((api, opts) => {
       "@babel/preset-stage-0 'useBuiltIns' option must be a boolean.",
     );
   }
+  if (typeof decoratorsLegacy !== "boolean") {
+    throw new Error(
+      "@babel/preset-stage-0 'decoratorsLegacy' option must be a boolean.",
+    );
+  }
+
+  if (decoratorsLegacy !== true) {
+    throw new Error(
+      "The new decorators proposal is not supported yet." +
+        ' You muse pass the `"decoratorsLegacy": true` option to' +
+        " @babel/preset-stage-0",
+    );
+  }
 
   return {
-    presets: [[presetStage1, { loose, useBuiltIns }]],
+    presets: [[presetStage1, { loose, useBuiltIns, decoratorsLegacy }]],
     plugins: [transformFunctionBind],
   };
 });

packages/babel-preset-stage-1/README.md

@@ -58,6 +58,12 @@ Enable "loose" transformations for any plugins in this preset that allow them.
 
 Will use the native built-in instead of trying to polyfill behavior for any plugins that require one.
 
+### `decoratorsLegacy`
+
+`boolean`, defaults to `false`.
+
+Use the legacy (stage 1) decorators syntax and behavior.
+
 ## References
 
 - Chapter "[The TC39 process for ECMAScript features](http://exploringjs.com/es2016-es2017/ch_tc39-process.html)" in "Exploring ES2016 and ES2017" by Axel Rauschmayer

packages/babel-preset-stage-1/package.json

@@ -9,7 +9,6 @@
   "main": "lib/index.js",
   "dependencies": {
     "@babel/helper-plugin-utils": "7.0.0-beta.44",
-    "@babel/plugin-proposal-decorators": "7.0.0-beta.44",
     "@babel/plugin-proposal-do-expressions": "7.0.0-beta.44",
     "@babel/plugin-proposal-export-default-from": "7.0.0-beta.44",
     "@babel/plugin-proposal-logical-assignment-operators": "7.0.0-beta.44",

packages/babel-preset-stage-1/src/index.js

@@ -1,7 +1,6 @@
 import { declare } from "@babel/helper-plugin-utils";
 import presetStage2 from "@babel/preset-stage-2";
 
-import transformDecorators from "@babel/plugin-proposal-decorators";
 import transformExportDefaultFrom from "@babel/plugin-proposal-export-default-from";
 import transformLogicalAssignmentOperators from "@babel/plugin-proposal-logical-assignment-operators";
 import transformOptionalChaining from "@babel/plugin-proposal-optional-chaining";
@@ -9,16 +8,10 @@ import transformPipelineOperator from "@babel/plugin-proposal-pipeline-operator"
 import transformNullishCoalescingOperator from "@babel/plugin-proposal-nullish-coalescing-operator";
 import transformDoExpressions from "@babel/plugin-proposal-do-expressions";
 
-export default declare((api, opts) => {
+export default declare((api, opts = {}) => {
   api.assertVersion(7);
 
-  let loose = false;
+  const { loose = false, useBuiltIns = false, decoratorsLegacy = false } = opts;
-  let useBuiltIns = false;
-
-  if (opts !== undefined) {
-    if (opts.loose !== undefined) loose = opts.loose;
-    if (opts.useBuiltIns !== undefined) useBuiltIns = opts.useBuiltIns;
-  }
 
   if (typeof loose !== "boolean") {
     throw new Error("@babel/preset-stage-1 'loose' option must be a boolean.");
@@ -28,11 +21,23 @@ export default declare((api, opts) => {
       "@babel/preset-stage-1 'useBuiltIns' option must be a boolean.",
     );
   }
+  if (typeof decoratorsLegacy !== "boolean") {
+    throw new Error(
+      "@babel/preset-stage-1 'decoratorsLegacy' option must be a boolean.",
+    );
+  }
+
+  if (decoratorsLegacy !== true) {
+    throw new Error(
+      "The new decorators proposal is not supported yet." +
+        ' You muse pass the `"decoratorsLegacy": true` option to' +
+        " @babel/preset-stage-1",
+    );
+  }
 
   return {
-    presets: [[presetStage2, { loose, useBuiltIns }]],
+    presets: [[presetStage2, { loose, useBuiltIns, decoratorsLegacy }]],
     plugins: [
-      [transformDecorators, { legacy: true }],
       transformExportDefaultFrom,
       transformLogicalAssignmentOperators,
       [transformOptionalChaining, { loose }],

packages/babel-preset-stage-2/README.md

@@ -58,6 +58,12 @@ Enable "loose" transformations for any plugins in this preset that allow them.
 
 Will use the native built-in instead of trying to polyfill behavior for any plugins that require one.
 
+### `decoratorsLegacy`
+
+`boolean`, defaults to `false`.
+
+Use the legacy (stage 1) decorators syntax and behavior.
+
 ## References
 
 - Chapter "[The TC39 process for ECMAScript features](http://exploringjs.com/es2016-es2017/ch_tc39-process.html)" in "Exploring ES2016 and ES2017" by Axel Rauschmayer

packages/babel-preset-stage-2/package.json

@@ -9,6 +9,7 @@
   "main": "lib/index.js",
   "dependencies": {
     "@babel/helper-plugin-utils": "7.0.0-beta.44",
+    "@babel/plugin-proposal-decorators": "7.0.0-beta.44",
     "@babel/plugin-proposal-export-namespace-from": "7.0.0-beta.44",
     "@babel/plugin-proposal-function-sent": "7.0.0-beta.44",
     "@babel/plugin-proposal-numeric-separator": "7.0.0-beta.44",

packages/babel-preset-stage-2/src/index.js

@@ -1,21 +1,16 @@
 import { declare } from "@babel/helper-plugin-utils";
 import presetStage3 from "@babel/preset-stage-3";
 
+import transformDecorators from "@babel/plugin-proposal-decorators";
 import transformFunctionSent from "@babel/plugin-proposal-function-sent";
 import transformExportNamespaceFrom from "@babel/plugin-proposal-export-namespace-from";
 import transformNumericSeparator from "@babel/plugin-proposal-numeric-separator";
 import transformThrowExpressions from "@babel/plugin-proposal-throw-expressions";
 
-export default declare((api, opts) => {
+export default declare((api, opts = {}) => {
   api.assertVersion(7);
 
-  let loose = false;
+  const { loose = false, useBuiltIns = false, decoratorsLegacy = false } = opts;
-  let useBuiltIns = false;
-
-  if (opts !== undefined) {
-    if (opts.loose !== undefined) loose = opts.loose;
-    if (opts.useBuiltIns !== undefined) useBuiltIns = opts.useBuiltIns;
-  }
 
   if (typeof loose !== "boolean") {
     throw new Error("@babel/preset-stage-2 'loose' option must be a boolean.");
@@ -25,10 +20,24 @@ export default declare((api, opts) => {
       "@babel/preset-stage-2 'useBuiltIns' option must be a boolean.",
     );
   }
+  if (typeof decoratorsLegacy !== "boolean") {
+    throw new Error(
+      "@babel/preset-stage-2 'decoratorsLegacy' option must be a boolean.",
+    );
+  }
+
+  if (decoratorsLegacy !== true) {
+    throw new Error(
+      "The new decorators proposal is not supported yet." +
+        ' You muse pass the `"decoratorsLegacy": true` option to' +
+        " @babel/preset-stage-2",
+    );
+  }
 
   return {
     presets: [[presetStage3, { loose, useBuiltIns }]],
     plugins: [
+      [transformDecorators, { legacy: decoratorsLegacy }],
       transformFunctionSent,
       transformExportNamespaceFrom,
       transformNumericSeparator,