From 6d6cdf6bafeed80dc8056e23a1014a8d7cd5377a Mon Sep 17 00:00:00 2001
From: Daniel Tschinder <daniel@tschinder.de>
Date: Tue, 28 Feb 2017 22:39:08 +0100
Subject: [PATCH] [7.0] Allow presets to be objects (#5385)

* Allow presets to be objects

* Improve logic to detect preset format
---
 .../file/options/option-manager.js            | 22 ++++++++++++-------
 ...15_default.js => es2015_default_object.js} |  0
 .../option-manager/presets/es2015_invalid.js  |  6 +++++
 .../presets/{es5.js => es5_object.js}         |  0
 packages/babel-core/test/option-manager.js    |  5 +++--
 5 files changed, 23 insertions(+), 10 deletions(-)
 rename packages/babel-core/test/fixtures/option-manager/presets/{es2015_default.js => es2015_default_object.js} (100%)
 create mode 100644 packages/babel-core/test/fixtures/option-manager/presets/es2015_invalid.js
 rename packages/babel-core/test/fixtures/option-manager/presets/{es5.js => es5_object.js} (100%)

diff --git a/packages/babel-core/src/transformation/file/options/option-manager.js b/packages/babel-core/src/transformation/file/options/option-manager.js
index 0dd3ecf70d..d50bd2139f 100644
--- a/packages/babel-core/src/transformation/file/options/option-manager.js
+++ b/packages/babel-core/src/transformation/file/options/option-manager.js
@@ -268,29 +268,30 @@ export default class OptionManager {
               JSON.stringify(dirname));
           }
         }
-        const presetFactory = this.getPresetFactoryForPreset(presetLoc || preset);
+        const resolvedPreset = this.loadPreset(presetLoc || preset, options, { dirname });
 
-        preset = presetFactory(context, options, { dirname });
+        if (onResolve) onResolve(resolvedPreset, presetLoc);
 
-        if (onResolve) onResolve(preset, presetLoc);
+        return resolvedPreset;
       } catch (e) {
         if (presetLoc) {
           e.message += ` (While processing preset: ${JSON.stringify(presetLoc)})`;
         }
         throw e;
       }
-
-      return preset;
     });
   }
 
-  getPresetFactoryForPreset(preset) {
+  /**
+   * Tries to load one preset. The input is either the module name of the preset,
+   * a function, or an object
+   */
+  loadPreset(preset, options, meta) {
     let presetFactory = preset;
     if (typeof presetFactory === "string") {
       presetFactory = require(presetFactory);
     }
 
-    // If the imported preset is a transpiled ES2015 module
     if (typeof presetFactory === "object" && presetFactory.__esModule) {
       if (presetFactory.default) {
         presetFactory = presetFactory.default;
@@ -299,12 +300,17 @@ export default class OptionManager {
       }
     }
 
+    // Allow simple object exports
+    if (typeof presetFactory === "object") {
+      return presetFactory;
+    }
+
     if (typeof presetFactory !== "function") {
       // eslint-disable-next-line max-len
       throw new Error(`Unsupported preset format: ${typeof presetFactory}. Expected preset to return a function.`);
     }
 
-    return presetFactory;
+    return presetFactory(context, options, meta);
   }
 
   normaliseOptions() {
diff --git a/packages/babel-core/test/fixtures/option-manager/presets/es2015_default.js b/packages/babel-core/test/fixtures/option-manager/presets/es2015_default_object.js
similarity index 100%
rename from packages/babel-core/test/fixtures/option-manager/presets/es2015_default.js
rename to packages/babel-core/test/fixtures/option-manager/presets/es2015_default_object.js
diff --git a/packages/babel-core/test/fixtures/option-manager/presets/es2015_invalid.js b/packages/babel-core/test/fixtures/option-manager/presets/es2015_invalid.js
new file mode 100644
index 0000000000..88437e1088
--- /dev/null
+++ b/packages/babel-core/test/fixtures/option-manager/presets/es2015_invalid.js
@@ -0,0 +1,6 @@
+// from code:
+// export default "string";
+'use strict';
+
+exports.__esModule = true;
+exports.default = "string";
diff --git a/packages/babel-core/test/fixtures/option-manager/presets/es5.js b/packages/babel-core/test/fixtures/option-manager/presets/es5_object.js
similarity index 100%
rename from packages/babel-core/test/fixtures/option-manager/presets/es5.js
rename to packages/babel-core/test/fixtures/option-manager/presets/es5_object.js
diff --git a/packages/babel-core/test/option-manager.js b/packages/babel-core/test/option-manager.js
index 582b61d8be..665a514668 100644
--- a/packages/babel-core/test/option-manager.js
+++ b/packages/babel-core/test/option-manager.js
@@ -76,11 +76,12 @@ describe("option-manager", () => {
     }
 
     presetTest("es5_function");
+    presetTest("es5_object");
     presetTest("es2015_default_function");
+    presetTest("es2015_default_object");
 
-    presetThrowsTest("es5", /Expected preset to return a function./);
-    presetThrowsTest("es2015_default", /Expected preset to return a function./);
     presetThrowsTest("es2015_named", /Preset must export a default export when using ES6 modules/);
+    presetThrowsTest("es2015_invalid", /Unsupported preset format: string/);
     presetThrowsTest("es5_invalid", /Unsupported preset format: string/);
   });
 });