Fix backward-compatibility of babel-preset-es2015 - fixes T7536

packages/babel-core/src/transformation/file/options/option-manager.js

@@ -273,6 +273,11 @@ export default class OptionManager {
           (presetLoc || "a preset") + " which does not accept options.");
       }
 
+      // For compatibility with babel-core < 6.13.x, allow presets to export an object with a
+      // a 'buildPreset' function that will return the preset itself, while still exporting a
+      // simple object (rather than a function), for supporting old Babel versions.
+      if (typeof val === "object" && val.buildPreset) val = val.buildPreset;
+
       if (typeof val === "function") val = val(context, options);
 
       if (typeof val !== "object") {

packages/babel-preset-es2015/src/index.js

@@ -1,4 +1,27 @@
-module.exports = function(context, opts) {
+/**
+ * This file is a bit of a mess. If you're looking at it as a reference for how to write a preset,
+ * I'd recommend looking only at `function preset(){}` and ignoring the rest, unless your new preset
+ * really needs to work on babel-core < 6.13.x, which is unlikely.
+ */
+
+/**
+ * This preset was originally an object, before function-based configurable presets were introduced.
+ * For backward-compatibility with anything that may have been loading this preset and expecting
+ * it to be a simple Babel config object, we maintain the old config here.
+ */
+module.exports = preset({});
+
+// For backward compatibility with babel-core < v6.13.x, we use the 'buildPreset' property
+// of the preset object for the preset creation function.
+Object.defineProperty(module.exports, "buildPreset", {
+  configurable: true,
+  writable: true,
+  enumerable: false,
+  value: preset,
+});
+
+
+function preset(context, opts) {
   const moduleTypes = ["commonjs", "amd", "umd", "systemjs"];
   let loose = false;
   let modules = "commonjs";
@@ -43,33 +66,5 @@ module.exports = function(context, opts) {
     // filter out falsy values
     ].filter(Boolean)
   };
-};
+}
 
-/**
- * This preset was originally an object, before function-based configurable presets were introduced.
- * For backward-compatibility with anything that may have been loading this preset and expecting
- * it to be a simple Babel config object, we maintain the old config here.
- */
-module.exports.plugins = [
-  require("babel-plugin-transform-es2015-template-literals"),
-  require("babel-plugin-transform-es2015-literals"),
-  require("babel-plugin-transform-es2015-function-name"),
-  require("babel-plugin-transform-es2015-arrow-functions"),
-  require("babel-plugin-transform-es2015-block-scoped-functions"),
-  require("babel-plugin-transform-es2015-classes"),
-  require("babel-plugin-transform-es2015-object-super"),
-  require("babel-plugin-transform-es2015-shorthand-properties"),
-  require("babel-plugin-transform-es2015-duplicate-keys"),
-  require("babel-plugin-transform-es2015-computed-properties"),
-  require("babel-plugin-transform-es2015-for-of"),
-  require("babel-plugin-transform-es2015-sticky-regex"),
-  require("babel-plugin-transform-es2015-unicode-regex"),
-  require("babel-plugin-check-es2015-constants"),
-  require("babel-plugin-transform-es2015-spread"),
-  require("babel-plugin-transform-es2015-parameters"),
-  require("babel-plugin-transform-es2015-destructuring"),
-  require("babel-plugin-transform-es2015-block-scoping"),
-  require("babel-plugin-transform-es2015-typeof-symbol"),
-  require("babel-plugin-transform-es2015-modules-commonjs"),
-  [require("babel-plugin-transform-regenerator"), { async: false, asyncGenerators: false }],
-];

packages/babel-preset-es2015/test/index.js

@@ -4,7 +4,8 @@ var expect = require("chai").expect;
 
 suite("es2015 preset", function () {
   test("exposes a function", function () {
-    expect(typeof es2015).to.equal("function");
+    // Changing this will break compatibility with babel-core < 6.13.x.
+    expect(typeof es2015).to.equal("object");
   });
 
   test("exposes a separate list of plugins", function () {
@@ -13,7 +14,7 @@ suite("es2015 preset", function () {
 
   test("doesn't throw with no options passed", function () {
     expect(function () {
-      es2015(null);
+      es2015.buildPreset(null);
     }).not.to.throw();
   })
 
@@ -21,7 +22,7 @@ suite("es2015 preset", function () {
     suite("loose", function () {
       test("throws on non-boolean value", function () {
         expect(function () {
-          es2015(null, { loose: 1});
+          es2015.buildPreset(null, { loose: 1});
         }).to.throw(/must be a boolean/);
       });
     });
@@ -29,25 +30,25 @@ suite("es2015 preset", function () {
     test("modules", function () {
       test("doesn't throw when passing one false", function () {
         expect(function () {
-          es2015(null, { loose: false });
+          es2015.buildPreset(null, { loose: false });
         }).not.to.throw();
       });
 
       test("doesn't throw when passing one of: 'commonjs', 'amd', 'umd', 'systemjs", function () {
         expect(function () {
-          es2015(null, { loose: "commonjs" });
+          es2015.buildPreset(null, { loose: "commonjs" });
         }).not.to.throw();
 
         expect(function () {
-          es2015(null, { loose: "amd" });
+          es2015.buildPreset(null, { loose: "amd" });
         }).not.to.throw();
 
         expect(function () {
-          es2015(null, { loose: "umd" });
+          es2015.buildPreset(null, { loose: "umd" });
         }).not.to.throw();
 
         expect(function () {
-          es2015(null, { loose: "systemjs" });
+          es2015.buildPreset(null, { loose: "systemjs" });
         }).not.to.throw();
       });
     });