fix(attributes): default empty dir to auto

README.md

@@ -67,7 +67,7 @@ const loader = async (project, title, language) => {
     console.warn(`Translations for locale ${language} could not be loaded.`, error);
     return {
       title,
-      attributes: { lang: language, dir: '' },
+      attributes: { lang: language, dir: 'auto' },
       notes: [],
       messages: []
     };
@@ -332,7 +332,7 @@ const data = resource.getData();
 ### Types
 
 - `MsgFormat` - `'MF1' | 'MF2' | 'NONE'`; the formatting syntax for a message.
-- `MsgAttributes` - `{ lang?: string; dir?: string; dnt?: boolean; format?: MsgFormat }`.
+- `MsgAttributes` - `{ lang?: string; dir?: string; dnt?: boolean; format?: MsgFormat }`. Omitted or empty `dir` resolves to `'auto'`.
 
 ### Pseudo-localization helpers
 

src/classes/MsgInterface/MsgInterface.ts

@@ -34,7 +34,7 @@ export const MSG_DEFAULT_FORMAT: MsgFormat = 'MF2';
 export type MsgAttributes = {
   /** BCP 47 language tag for the content (for example, `en` or `zh-Hans`). */
   lang?: string
-  /** Text direction: typically `ltr`, `rtl`, or `auto`. */
+  /** Text direction: typically `ltr`, `rtl`, or `auto`. Omitted or empty values resolve to `'auto'`. */
   dir?: string
   /** When true, the content should not be translated (Do Not Translate). */
   dnt?: boolean

src/classes/MsgMessage/MsgMessage.ts

@@ -1,6 +1,7 @@
 import { MessageFormat, type MessageFormatOptions } from "messageformat";
 import { mf1ToMessage } from "@messageformat/icu-messageformat-1";
-import { MsgInterface, DEFAULT_ATTRIBUTES, MSG_DEFAULT_FORMAT, type MsgAttributes, type MsgFormat, type MsgNote, type NoteTypes } from "../MsgInterface/MsgInterface.js";
+import { MsgInterface, MSG_DEFAULT_FORMAT, type MsgAttributes, type MsgFormat, type MsgNote, type NoteTypes } from "../MsgInterface/MsgInterface.js";
+import { applyAttributes } from "../../lib/apply-attributes.js";
 
 /**
  * Plain data used to create a {@link MsgMessage}.
@@ -35,8 +36,8 @@ export class MsgMessage implements MsgInterface {
     this._key = key;
     this._value = value;
 
-    // merge in any attributes
-    this._attributes = attributes ? {...DEFAULT_ATTRIBUTES, ...attributes} : {};
+    // Always apply library defaults so omitted or empty `dir` becomes `'auto'`.
+    this._attributes = applyAttributes(attributes);
 
     // add any notes
     if (notes) {

src/classes/MsgResource/MsgResource.ts

@@ -1,5 +1,6 @@
 import { type MsgMessageData, MsgMessage } from "../MsgMessage/MsgMessage.js";
-import { DEFAULT_ATTRIBUTES, MSG_DEFAULT_FORMAT, MsgInterface, type MsgAttributes, type MsgNote, type NoteTypes } from "../MsgInterface/MsgInterface.js";
+import { MSG_DEFAULT_FORMAT, MsgInterface, type MsgAttributes, type MsgNote, type NoteTypes } from "../MsgInterface/MsgInterface.js";
+import { applyAttributes } from "../../lib/apply-attributes.js";
 import { MsgProject } from "../MsgProject/MsgProject.js";
 import { pseudoLocalize } from "../../lib/pseudo-localize.js";
 
@@ -61,7 +62,7 @@ export class MsgResource extends Map<string, MsgMessage> implements MsgInterface
     this._title = title;
 
     // Inherit the project's format unless the resource specifies its own.
-    this._attributes = {...DEFAULT_ATTRIBUTES, format: project.format, ...attributes};
+    this._attributes = applyAttributes(attributes, { format: project.format });
     this._project = project;
 
     if (notes) {
@@ -96,7 +97,7 @@ export class MsgResource extends Map<string, MsgMessage> implements MsgInterface
 
   /** Replaces the resource's locale and formatting metadata. */
   public set attributes(attributes: MsgAttributes) {
-    this._attributes = attributes;
+    this._attributes = applyAttributes(attributes);
   }
 
   /** Notes attached to this resource for translators and tooling. */

src/lib/apply-attributes.ts

@@ -0,0 +1,18 @@
+import { DEFAULT_ATTRIBUTES, type MsgAttributes } from '../classes/MsgInterface/MsgInterface.js';
+
+/**
+ * Merges {@link DEFAULT_ATTRIBUTES} with optional extras and caller attributes.
+ *
+ * An empty-string `dir` is treated as unset and becomes `'auto'`. This helper
+ * is module-internal (not re-exported from the public API).
+ */
+export function applyAttributes(
+  attributes?: MsgAttributes,
+  extras?: MsgAttributes
+): MsgAttributes {
+  const merged: MsgAttributes = { ...DEFAULT_ATTRIBUTES, ...extras, ...attributes };
+  if (!merged.dir) {
+    merged.dir = 'auto';
+  }
+  return merged;
+}

src/tests/MsgMessage.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, test } from 'vitest';
 import { MsgMessage } from '../classes/MsgMessage/MsgMessage.js';
-import { MsgNote } from '../classes/MsgInterface/MsgInterface.js';
+import { DEFAULT_ATTRIBUTES, MsgNote } from '../classes/MsgInterface/MsgInterface.js';
 
 
 describe('MsgMessage tests', () => {
@@ -13,7 +13,8 @@ describe('MsgMessage tests', () => {
 
     expect(msg1.key).toBe('my-key');
     expect(msg1.value).toBe('My Value');
-    expect(msg1.attributes).toStrictEqual({});
+    expect(msg1.attributes).toStrictEqual(DEFAULT_ATTRIBUTES);
+    expect(msg1.attributes.dir).toBe('auto');
     expect(msg1.notes).toStrictEqual([]);
   });
 
@@ -65,7 +66,7 @@ describe('MsgMessage tests', () => {
 
     expect(msg4.key).toBe('my-key');
     expect(msg4.value).toBe('My Value');
-    expect(msg4.attributes).toStrictEqual({});
+    expect(msg4.attributes).toStrictEqual(DEFAULT_ATTRIBUTES);
     expect(msg4.notes).toStrictEqual([{type: 'DESCRIPTION', content: 'This is a test description'}]);
     expect(msg4.notes.length).toBe(1);
 
@@ -150,13 +151,49 @@ describe('MsgMessage tests', () => {
       value: 'My Value'
     });
 
-    expect(msg5.attributes).toStrictEqual({});
+    expect(msg5.attributes).toStrictEqual(DEFAULT_ATTRIBUTES);
+  });
+
+  test('Create with empty-string dir normalizes to auto', () => {
+    const msg = MsgMessage.create({
+      key: 'my-key',
+      value: 'My Value',
+      attributes: {
+        lang: 'en',
+        dir: ''
+      }
+    });
+
+    expect(msg.attributes.lang).toBe('en');
+    expect(msg.attributes.dir).toBe('auto');
+  });
+
+  test('Create with explicit dir is preserved', () => {
+    const ltr = MsgMessage.create({
+      key: 'ltr-key',
+      value: 'Left',
+      attributes: { dir: 'ltr' }
+    });
+    const rtl = MsgMessage.create({
+      key: 'rtl-key',
+      value: 'Right',
+      attributes: { dir: 'rtl' }
+    });
+    const auto = MsgMessage.create({
+      key: 'auto-key',
+      value: 'Auto',
+      attributes: { dir: 'auto' }
+    });
+
+    expect(ltr.attributes.dir).toBe('ltr');
+    expect(rtl.attributes.dir).toBe('rtl');
+    expect(auto.attributes.dir).toBe('auto');
   });
 
   const output = JSON.stringify({
     "key": "my-key",
     "value": "My Value",
-    "attributes": {}
+    "attributes": DEFAULT_ATTRIBUTES
   }, null, 2);
 
   test('Test generic functions', () => {

src/tests/MsgResource.test.ts

@@ -152,6 +152,35 @@ describe('MsgResource tests', () => {
     expect(resource.attributes.dir).toBe('auto'); // default value
   });
 
+  test('MsgResource: "create" normalizes empty-string dir to auto', () => {
+    const project = MsgProject.create(testProjectData);
+    const resource = MsgResource.create({
+      title: 'TestResource',
+      attributes: {
+        lang: 'en',
+        dir: ''
+      }
+    }, project);
+
+    expect(resource.attributes.lang).toBe('en');
+    expect(resource.attributes.dir).toBe('auto');
+  });
+
+  test('MsgResource: "create" preserves explicit dir', () => {
+    const project = MsgProject.create(testProjectData);
+    const ltr = MsgResource.create({
+      title: 'LtrResource',
+      attributes: { lang: 'en', dir: 'ltr' }
+    }, project);
+    const rtl = MsgResource.create({
+      title: 'RtlResource',
+      attributes: { lang: 'ar', dir: 'rtl' }
+    }, project);
+
+    expect(ltr.attributes.dir).toBe('ltr');
+    expect(rtl.attributes.dir).toBe('rtl');
+  });
+
   test('MsgResource: title getter and setter', () => {
     const project = MsgProject.create(testProjectData);
     const resource = MsgResource.create({
@@ -197,6 +226,10 @@ describe('MsgResource tests', () => {
     expect(resource.attributes.lang).toBe('fr');
     expect(resource.attributes.dir).toBe('rtl');
     expect(resource.attributes.dnt).toBe(true);
+
+    resource.attributes = { lang: 'de', dir: '' };
+    expect(resource.attributes.lang).toBe('de');
+    expect(resource.attributes.dir).toBe('auto');
   });
 
   test('MsgResource: notes getter and setter', () => {
@@ -279,6 +312,22 @@ describe('MsgResource tests', () => {
     expect(message?.attributes.dnt).toBe(true); // overridden
   });
 
+  test('MsgResource: "add" method normalizes empty-string dir override to auto', () => {
+    const project = MsgProject.create(testProjectData);
+    const resource = MsgResource.create({
+      title: 'TestResource',
+      attributes: {
+        lang: 'en',
+        dir: 'ltr'
+      }
+    }, project);
+
+    resource.add('test-key', 'Test Value', { dir: '' });
+
+    expect(resource.get('test-key')?.attributes.dir).toBe('auto');
+    expect(resource.get('test-key')?.attributes.lang).toBe('en');
+  });
+
   test('MsgResource: "add" method with notes', () => {
     const project = MsgProject.create(testProjectData);
     const resource = MsgResource.create({