update

test/list-join.test.js

@@ -0,0 +1,53 @@
+'use strict';
+const assert = require('node:assert');
+const fs = require('node:fs');
+const os = require('node:os');
+const path = require('node:path');
+
+const Database = require('better-sqlite3');
+
+const tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'clip-join-'));
+const db = new Database(path.join(tmp, 'h.db'));
+db.exec(`
+  CREATE TABLE clips (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    type TEXT, text TEXT, image BLOB, preview TEXT,
+    top_at REAL, created_at REAL NOT NULL
+  );
+  CREATE TABLE favorites (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    source_clip_id INTEGER UNIQUE, favorited_at REAL NOT NULL
+  );
+`);
+const now = Date.now()/1000;
+// created_at 必须互不相同，否则 ORDER BY created_at DESC 的次序未定义，断言就是碰运气
+db.prepare('INSERT INTO clips(type,text,preview,top_at,created_at) VALUES(?,?,?,?,?)').run('text','a','a',null,now - 2);
+db.prepare('INSERT INTO clips(type,text,preview,top_at,created_at) VALUES(?,?,?,?,?)').run('text','b','b',null,now - 1);
+db.prepare('INSERT INTO clips(type,text,preview,top_at,created_at) VALUES(?,?,?,?,?)').run('text','c','c',null,now);
+const favInfo = db.prepare('INSERT INTO favorites(source_clip_id, favorited_at) VALUES(?,?)').run(2, now);
+const favIdOfClip2 = favInfo.lastInsertRowid;   // = favorites.id，不是 clip.id
+
+let passed = 0;
+function check(name, fn) {
+  try { fn(); console.log('  ok -', name); passed++; }
+  catch (e) { console.error('  FAIL -', name, e.message); process.exitCode = 1; }
+}
+
+check('LEFT JOIN returns one row per clip with fav_id when matched', () => {
+  const rows = db.prepare(`
+    SELECT c.id, c.text, f.id AS fav_id
+    FROM clips c
+    LEFT JOIN favorites f ON f.source_clip_id = c.id
+    ORDER BY c.created_at DESC
+  `).all();
+  assert.strictEqual(rows.length, 3, 'JOIN 不应放大行数');
+  // created_at DESC → c(3), b(2), a(1)；被收藏的是 clip 2 = 中间那条
+  assert.deepStrictEqual(rows.map(r => r.id), [3, 2, 1]);
+  assert.strictEqual(rows[0].fav_id, null);
+  // fav_id 是 favorites 表的主键，不是 source_clip_id —— 这两个值以前被搞混了
+  assert.strictEqual(rows[1].fav_id, favIdOfClip2);
+  assert.notStrictEqual(rows[1].fav_id, rows[1].id, 'favId 与 clipId 是不同的命名空间');
+  assert.strictEqual(rows[2].fav_id, null);
+});
+
+db.close();