Metadata -- create basic object

package.json

@@ -1,6 +1,6 @@
 {
   "name": "music21j",
-  "version": "0.17.13",
+  "version": "0.17.14",
   "description": "A toolkit for computer-aided musicology, Javascript version",
   "main": "releases/music21.debug.js",
   "typings": "releases/src/main.d.ts",

src/base.ts

@@ -4,7 +4,7 @@
  *
  * does not load the other modules.
  *
- * Copyright (c) 2013-24, Michael Scott Asato Cuthbert
+ * Copyright (c) 2013-24, Michael Scott Asato Cuthbert, BSD License
  * Based on music21 (=music21p), Copyright (c) 2006-24, Michael Scott Asato Cuthbert
  *
  * module for Music21Objects

src/main.ts

@@ -62,6 +62,7 @@ import * as interval from './interval';
 import * as key from './key';
 import * as keyboard from './keyboard';
 import * as layout from './layout';
+import * as metadata from './metadata';
 import * as meter from './meter';
 import * as miditools from './miditools';
 import * as musicxml from './musicxml';
@@ -85,6 +86,7 @@ import * as webmidi from './webmidi';
 
 import { debug } from './debug';
 
+export const VERSION = '0.17.14';
 
 export {
     MIDI,
@@ -120,6 +122,7 @@ export {
     key,
     keyboard,
     layout,
+    metadata,
     meter,
     miditools,
     musicxml,
@@ -142,6 +145,4 @@ export {
     webmidi,
 };
 
-export const VERSION = '0.17.12';
-
 parseLoader.runConfiguration();

src/metadata.ts

@@ -0,0 +1,28 @@
+/**
+ * music21j -- Javascript reimplementation of Core music21p features.
+ * music21/metadata -- Very basic metadata object
+ *
+ * Copyright (c) 2013-25, Michael Scott Asato Cuthbert, BSD License
+ * Based on music21 (=music21p), Copyright (c) 2006-25, Michael Scott Asato Cuthbert
+ */
+
+import { Music21Object } from './base';
+
+export class Metadata extends Music21Object {
+    title: string|undefined = undefined;
+    composer: string|undefined = undefined;
+
+    constructor(vars: any = {}) {
+        super(vars);
+        if ('title' in vars) {
+            this.title = vars.title;
+        }
+        if ('composer' in vars) {
+            this.composer = vars.composer;
+        }
+    }
+
+    static get className() { return 'music21.metadata.Metadata'; }
+}
+
+export default Metadata;

src/stream.ts

@@ -30,6 +30,7 @@ import * as common from './common';
 import * as derivation from './derivation';
 import { Duration } from './duration';
 import * as instrument from './instrument';
+import * as metadata from './metadata';
 import * as meter from './meter';
 import * as note from './note';
 import * as pitch from './pitch';
@@ -557,6 +558,24 @@ export class Stream<ElementType extends base.Music21Object = base.Music21Object>
         }
     }
 
+    get metadata(): metadata.Metadata {
+        let out_metadata = this._firstElementContext('metadata') as metadata.Metadata;
+        if (out_metadata === undefined) {
+            out_metadata = new metadata.Metadata();
+            this.insert(0.0, out_metadata);
+        }
+        return out_metadata;
+    }
+
+    set metadata(newMetadata: metadata.Metadata) {
+        const oldMetadata = this._firstElementContext('metadata') as metadata.Metadata;
+        if (oldMetadata !== undefined) {
+            this.replace(oldMetadata, newMetadata);
+        } else {
+            this.insert(0.0, newMetadata);
+        }
+    }
+
     get clef(): clef.Clef {
         return this.getSpecialContext('clef', false) as clef.Clef;
     }

tests/loadAll.ts

@@ -13,6 +13,7 @@ import figuredBass from './moduleTests/figuredBass';
 import interval from './moduleTests/interval';
 import iterator from './moduleTests/stream/iterator';
 import key from './moduleTests/key';
+import metadata  from './moduleTests/metadata';
 import meter from './moduleTests/meter';
 import note from './moduleTests/note';
 import pitch from './moduleTests/pitch';
@@ -43,6 +44,7 @@ const allTests = {
     interval,
     iterator,
     key,
+    metadata,
     meter,
     note,
     pitch,

tests/moduleTests/metadata.ts

@@ -0,0 +1,28 @@
+import * as QUnit from 'qunit';
+import * as music21 from '../../src/main';
+
+const { test } = QUnit;
+
+
+export default function tests() {
+    test('music21.metadata.Metadata', assert => {
+        const m = new music21.metadata.Metadata({title: 'Aloha Oe', composer: 'Liliuokalani'});
+        assert.equal(m.title, 'Aloha Oe');
+        assert.equal(m.composer, 'Liliuokalani');
+    });
+
+    test('music21.metadata.Metadata in Streams', assert => {
+        const s = new music21.stream.Score();
+        s.insert(0.0, new music21.note.Note('C4'));
+        s.metadata.title = 'Aloha Oe';
+        assert.equal(s.metadata.title, 'Aloha Oe');
+        const old_md = s.metadata;
+
+        const md2 = new music21.metadata.Metadata({title: 'Pink Pony Club'});
+        s.metadata = md2;
+        assert.equal(s.metadata.title, 'Pink Pony Club');
+        assert.equal(old_md.title, 'Aloha Oe');
+        assert.ok(Array.from(s).includes(md2));
+        assert.notOk(Array.from(s).includes(old_md));
+    });
+}