Do not transform Platform.select() calls using dynamic properties

Reviewed By: davidaurelio

Differential Revision: D7085775

fbshipit-source-id: 348e43312ecb8298c14b202f209850b54d9b7b12

packages/metro/src/JSTransformer/worker/__tests__/inline-plugin-test.js

@@ -231,6 +231,32 @@ describe('inline constants', () => {
     );
   });
 
+  it('does not inline Platform.select in the code when some of the properties are dynamic', () => {
+    const code = `function a() {
+      const COMPUTED_IOS = 'ios';
+      const COMPUTED_ANDROID = 'android';
+      var a = Platform.select({[COMPUTED_ANDROID]: 1, [COMPUTED_IOS]: 2, default: 3});
+    }`;
+    const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
+    expect(toString(ast)).toEqual(normalize(code));
+  });
+
+  it('does not inline Platform.select when all properties are dynamic', () => {
+    const code = `function a() {
+      var a = Platform.select({[COMPUTED_ANDROID]: 1, [COMPUTED_IOS]: 2});
+    }`;
+    const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
+    expect(toString(ast)).toEqual(normalize(code));
+  });
+
+  it('does not inline Platform.select if it receives a non-object', () => {
+    const code = `function a() {
+      var a = Platform.select(foo);
+    }`;
+    const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
+    expect(toString(ast)).toEqual(normalize(code));
+  });
+
   it('replaces Platform.select in the code if Platform is a top level import', () => {
     const code = `
       var Platform = require('Platform');

packages/metro/src/JSTransformer/worker/inline-plugin.js

@@ -70,6 +70,20 @@ function inlinePlugin(context: Context) {
     return property ? property.value : fallback();
   }
 
+  function hasStaticProperties(objectExpression) {
+    if (!t.isObjectExpression(objectExpression)) {
+      return false;
+    }
+
+    return objectExpression.properties.every(p => {
+      if (p.computed) {
+        return false;
+      }
+
+      return t.isIdentifier(p.key) || t.isStringLiteral(p.key);
+    });
+  }
+
   return {
     visitor: {
       Identifier(path: Object, state: Object) {
@@ -99,13 +113,12 @@ function inlinePlugin(context: Context) {
         const opts = state.opts;
 
         if (isPlatformSelectNode(node, scope, opts.isWrapped)) {
-          const fallback = () =>
-            findProperty(arg, 'default', () => t.identifier('undefined'));
-          const replacement = t.isObjectExpression(arg)
-            ? findProperty(arg, opts.platform, fallback)
-            : node;
+          if (hasStaticProperties(arg)) {
+            const fallback = () =>
+              findProperty(arg, 'default', () => t.identifier('undefined'));
 
-          path.replaceWith(replacement);
+            path.replaceWith(findProperty(arg, opts.platform, fallback));
+          }
         } else if (isPlatformOSSelect(node, scope, opts.isWrapped)) {
           path.replaceWith(
             getReplacementForPlatformOSSelect(node, opts.platform),