notes: pure db.json helpers, node-tested

The parsing, sorting and transforms the notes page needs, kept free of any
file or process so node can test them.

Ids and files stay strings: notes.sh writes them with jq --arg and looks a
note up with select(.id == $i), so a number would stop the CLI finding a
note the page wrote. sorted() copies rather than reorders, and an entry
whose file is missing or non-numeric sorts last and formats as blank
instead of NaN.

1 files changed, 70 insertions, 0 deletions

diff --git a/desktop/modules/notes/test_notes.js b/desktop/modules/notes/test_notes.js
new file mode 100644
index 0000000..955369c
--- /dev/null
+++ b/desktop/modules/notes/test_notes.js
@@ -0,0 +1,70 @@
+// Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// Run: node desktop/modules/notes/test_notes.js
+// Notes.js is a QML library, so its .pragma line is stripped before node
+// evaluates it, as test_clip.js does for Clip.js.
+
+const fs = require("fs");
+const assert = require("assert");
+
+const src = fs.readFileSync(__dirname + "/Notes.js", "utf8")
+    .replace(/^\.pragma library$/m, "");
+const N = new Function(src + "\nreturn { parse, stringify, sorted, formatDate, nextId,"
+    + " filter, addNote, updateNote, removeNote, setLastpull };")();
+
+const db = {
+    params: { version: "0.4git", dbversion: "0.4git_1" },
+    git: { lastpull: "1700000000" },
+    notes: [
+        { id: "1", title: "a", file: "999" },
+        { id: "2", title: "b", file: "1000" },
+        { id: "3", title: "c", file: "300" },
+    ],
+};
+
+// numeric, not lexicographic: 1000 > 999 > 300
+assert.deepStrictEqual(N.sorted(db.notes).map(n => n.id), ["2", "1", "3"]);
+assert.strictEqual(db.notes[0].id, "1");                 // input not reordered
+
+// a missing or non-numeric file sorts last, input order, and formats as ""
+const bad = [{ id: "1", title: "x" }, { id: "2", title: "y", file: "abc" },
+             { id: "3", title: "z", file: "10" }];
+assert.deepStrictEqual(N.sorted(bad).map(n => n.id), ["3", "1", "2"]);
+assert.strictEqual(N.formatDate(undefined), "");
+assert.strictEqual(N.formatDate("abc"), "");
+assert.match(N.formatDate("1000"), /^\d{2}\/\d{2}\/\d{4} \d{2}:\d{2}$/);
+
+assert.strictEqual(N.nextId(db.notes), "4");
+assert.strictEqual(N.nextId([]), "1");
+
+// the whole object round-trips; params and git are kept
+assert.deepStrictEqual(N.parse(N.stringify(db)), db);
+assert.deepStrictEqual(N.parse("not json"), { notes: [] });
+assert.deepStrictEqual(N.parse('{"a":1}'), { notes: [] });
+
+// pure transforms preserve everything else and do not mutate
+const added = N.addNote(db, "T", "1750");
+assert.strictEqual(added.notes.length, 4);
+assert.deepStrictEqual(added.notes[3], { id: "4", title: "T", file: "1750" });
+assert.strictEqual(db.notes.length, 3);
+assert.deepStrictEqual(added.params, db.params);
+assert.deepStrictEqual(added.git, db.git);
+assert.deepStrictEqual(N.removeNote(added, "4"), db);
+assert.strictEqual(N.updateNote(db, "2", "Renamed").notes[1].title, "Renamed");
+assert.deepStrictEqual(N.updateNote(db, "99", "x"), db);
+assert.strictEqual(N.setLastpull(db, 1234).git.lastpull, "1234");
+assert.strictEqual(db.git.lastpull, "1700000000");
+
+assert.deepStrictEqual(N.filter(db.notes, "  A ").map(n => n.id), ["1"]);
+assert.strictEqual(N.filter(db.notes, "").length, 3);
+
+console.log("test_notes: ok");