Remove description after extracting Message Descriptors

This adds back the removal of `description` fields after extracting
the Message Descriptor in a way that works if the plugin is added
multiple times.

See #28

Author: ericf

README.md

@@ -16,6 +16,8 @@ $ npm install babel-plugin-react-intl
 
 The default message descriptors for the app's default language will be extracted from: `defineMessages()`, `<FormattedMessage>`, and `<FormattedHTMLMessage>`; all of which are named exports of the React Intl package.
 
+If a message descriptor has a `description`, it'll be removed from the source after it's extracted to save bytes since it isn't used at runtime.
+
 ### Via `.babelrc` (Recommended)
 
 **.babelrc**

src/index.js

@@ -20,7 +20,9 @@ const FUNCTION_NAMES = [
 
 const DESCRIPTOR_PROPS = new Set(['id', 'description', 'defaultMessage']);
 
-export default function () {
+const EXTRACTED_TAG = Symbol('ReactIntlExtracted');
+
+export default function ({types: t}) {
     function getModuleSourceName(opts) {
         return opts.moduleSourceName || 'react-intl';
     }
@@ -153,6 +155,14 @@ export default function () {
         return importedNames.some((name) => path.referencesImport(mod, name));
     }
 
+    function tagAsExtracted(path) {
+        path.node[EXTRACTED_TAG] = true;
+    }
+
+    function wasExtracted(path) {
+        return !!path.node[EXTRACTED_TAG];
+    }
+
     return {
         visitor: {
             Program: {
@@ -192,10 +202,13 @@ export default function () {
             },
 
             JSXOpeningElement(path, state) {
-                const {file, opts}     = state;
-                const moduleSourceName = getModuleSourceName(opts);
+                if (wasExtracted(path)) {
+                    return;
+                }
 
-                let name = path.get('name');
+                const {file, opts} = state;
+                const moduleSourceName = getModuleSourceName(opts);
+                const name = path.get('name');
 
                 if (name.referencesImport(moduleSourceName, 'FormattedPlural')) {
                     file.log.warn(
@@ -231,7 +244,20 @@ export default function () {
                         descriptor = evaluateMessageDescriptor(descriptor, {
                             isJSXSource: true,
                         });
+
                         storeMessage(descriptor, path, state);
+
+                        // Remove description since it's not used at runtime.
+                        attributes.some((attr) => {
+                            let ketPath = attr.get('name');
+                            if (getMessageDescriptorKey(ketPath) === 'description') {
+                                attr.remove();
+                                return true;
+                            }
+                        });
+
+                        // Tag the AST node so we don't try to extract it twice.
+                        tagAsExtracted(path);
                     }
                 }
             },
@@ -254,6 +280,10 @@ export default function () {
                 function processMessageObject(messageObj) {
                     assertObjectExpression(messageObj);
 
+                    if (wasExtracted(messageObj)) {
+                        return;
+                    }
+
                     let properties = messageObj.get('properties');
 
                     let descriptor = createMessageDescriptor(
@@ -266,6 +296,21 @@ export default function () {
                     // Evaluate the Message Descriptor values, then store it.
                     descriptor = evaluateMessageDescriptor(descriptor);
                     storeMessage(descriptor, messageObj, state);
+
+                    // Remove description since it's not used at runtime.
+                    messageObj.replaceWith(t.objectExpression([
+                        t.objectProperty(
+                            t.stringLiteral('id'),
+                            t.stringLiteral(descriptor.id)
+                        ),
+                        t.objectProperty(
+                            t.stringLiteral('defaultMessage'),
+                            t.stringLiteral(descriptor.defaultMessage)
+                        ),
+                    ]));
+
+                    // Tag the AST node so we don't try to extract it twice.
+                    tagAsExtracted(messageObj);
                 }
 
                 if (referencesImport(callee, moduleSourceName, FUNCTION_NAMES)) {

test/fixtures/removeDescriptions/actual.js

@@ -0,0 +1,22 @@
+import React, {Component} from 'react';
+import {defineMessages, FormattedMessage} from 'react-intl';
+
+const messages = defineMessages({
+    foo: {
+        id: 'greeting-user',
+        description: 'Greeting the user',
+        defaultMessage: 'Hello, {name}',
+    },
+});
+
+export default class Foo extends Component {
+    render() {
+        return (
+            <FormattedMessage
+                id='greeting-world'
+                description='Greeting to the world'
+                defaultMessage='Hello World!'
+            />
+        );
+    }
+}

test/index.js

@@ -15,6 +15,7 @@ const skipTests = [
     'extractSourceLocation',
     'moduleSourceName',
     'icuSyntax',
+    'removeDescriptions',
 ];
 
 const fixturesDir = path.join(__dirname, 'fixtures');
@@ -74,6 +75,22 @@ describe('options', () => {
         }
     });
 
+    it('removes descriptions when plugin is applied more than once', () => {
+        const fixtureDir = path.join(fixturesDir, 'removeDescriptions');
+
+        try {
+            transform(path.join(fixtureDir, 'actual.js'), {
+                enforceDescriptions: true,
+            }, {
+                multiplePasses: true,
+            });
+            assert(true);
+        } catch (e) {
+            console.error(e);
+            assert(false);
+        }
+    });
+
     it('respects moduleSourceName', () => {
         const fixtureDir = path.join(fixturesDir, 'moduleSourceName');
 
@@ -133,13 +150,18 @@ const BASE_OPTIONS = {
     messagesDir: baseDir,
 };
 
-function transform(filePath, options = {}) {
+function transform(filePath, options = {}, {multiplePasses = false} = {}) {
+    function getPluginConfig() {
+        return [plugin, {
+            ...BASE_OPTIONS,
+            ...options,
+        }];
+    }
+
     return babel.transformFileSync(filePath, {
-        plugins: [
-            [plugin, {
-                ...BASE_OPTIONS,
-                ...options,
-            }],
-        ],
+        plugins: multiplePasses ? [
+            getPluginConfig(),
+            getPluginConfig(),
+        ] : [getPluginConfig()],
     }).code;
 }