feat(babel-plugin-react-intl): output file with empty [] if src has no messages

For build systems like bazel that relies on specific output mapping, not
writing out a file can cause issues.
This also fix #553 as a side-effect.

Author: Long Ho

packages/babel-plugin-react-intl/src/index.ts

@@ -5,8 +5,7 @@
  */
 
 import * as p from 'path';
-import {writeFileSync} from 'fs';
-import {mkdirpSync} from 'fs-extra';
+import {outputJSONSync} from 'fs-extra';
 import {parse} from 'intl-messageformat-parser/dist';
 const {declare} = require('@babel/helper-plugin-utils') as any;
 import {types as t, PluginObj} from '@babel/core';
@@ -342,7 +341,7 @@ export default declare((api: any, options: OptionsSchema) => {
       const descriptors = Array.from(messages.values());
       state.metadata['react-intl'] = {messages: descriptors};
 
-      if (basename && messagesDir && descriptors.length > 0) {
+      if (basename && messagesDir) {
         // Make sure the relative path is "absolute" before
         // joining it with the `messagesDir`.
         let relativePath = p.join(p.sep, p.relative(process.cwd(), filename));
@@ -364,10 +363,7 @@ export default declare((api: any, options: OptionsSchema) => {
           basename + '.json'
         );
 
-        const messagesFile = JSON.stringify(descriptors, null, 2);
-
-        mkdirpSync(p.dirname(messagesFilename));
-        writeFileSync(messagesFilename, messagesFile);
+        outputJSONSync(messagesFilename, descriptors);
       }
     },
 

packages/babel-plugin-react-intl/test/__snapshots__/index.test.ts.snap

@@ -270,6 +270,40 @@ Array [
 ]
 `;
 
+exports[`emit asserts for:  output match: empty 1`] = `
+Object {
+  "messages": Array [],
+}
+`;
+
+exports[`emit asserts for:  output match: empty 2`] = `
+"\\"use strict\\";
+
+Object.defineProperty(exports, \\"__esModule\\", {
+  value: true
+});
+exports.default = void 0;
+
+var _react = _interopRequireWildcard(require(\\"react\\"));
+
+var _macro = require(\\"@formatjs/macro\\");
+
+function _getRequireWildcardCache() { if (typeof WeakMap !== \\"function\\") return null; var cache = new WeakMap(); _getRequireWildcardCache = function () { return cache; }; return cache; }
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== \\"object\\" && typeof obj !== \\"function\\") { return { default: obj }; } var cache = _getRequireWildcardCache(); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }
+
+class Foo extends _react.Component {
+  render() {
+    return _react.default.createElement(\\"div\\", null);
+  }
+
+}
+
+exports.default = Foo;"
+`;
+
+exports[`emit asserts for:  output match: empty 3`] = `Array []`;
+
 exports[`emit asserts for:  output match: enforceDefaultMessage 1`] = `
 Object {
   "messages": Array [
@@ -500,7 +534,7 @@ class Foo extends _react.Component {
       id: \\"actual.js.foo.bar.zoo.12.object\\",
       defaultMessage: \\"Hello World!\\"
     }), _react.default.createElement(_reactIntl.FormattedMessage, {
-      id: \\"HELLO..5.object\\",
+      id: \\"actual.js..5.object\\",
       defaultMessage: \\"NO ID\\"
     }), _react.default.createElement(_reactIntl.FormattedHTMLMessage, {
       id: \\"actual.js.foo.bar.delta.21.string\\",
@@ -542,7 +576,7 @@ Array [
       "metadata": "Additional metadata content.",
       "text": "Something for the translator. Another description",
     },
-    "id": "HELLO..5.object",
+    "id": "actual.js..5.object",
   },
   Object {
     "defaultMessage": "<h1>Hello World!</h1>",

packages/babel-plugin-react-intl/test/fixtures/empty/actual.js

@@ -0,0 +1,8 @@
+import React, {Component} from 'react';
+import {_} from '@formatjs/macro';
+
+export default class Foo extends Component {
+  render() {
+    return <div></div>;
+  }
+}