IndexedDB 唯一约束校验与游标去重实践

概述唯一索引能防止重复。本文演示插入检查与去重策略。建表与插入校验function openDB(name) { return new Promise((resolve, reject) => { const r = indexedDB.open(name, 1); r.onupgradeneeded = () => { const db = r.result; const s = db.createObjectStore('users', { keyPath: 'id' }); s.createIndex('byEmail', 'email', { unique: true }); }; r.onsuccess = () => resolve(r.result); r.onerror = () => reject(r.error); }); } async function insertUser(rec) { const db = await openDB('udb'); const tx = db.transaction('users', 'readwrite'); const idx = tx.objectStore('users').index('byEmail'); const req = idx.get(rec.email); const exists = await new Promise((res, rej) => { req.onsuccess = () => res(!!req.result); req.onerror = () => rej(req.error); }); if (exists) { db.close(); throw new Error('duplicate email'); } tx.objectStore('users').put(rec); await new Promise((res, rej) => { tx.oncomplete = res; tx.onerror = () => rej(tx.error); }); db.close(); }