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dexie

caution
npm add dexie dexie-react-hooks
  • schema
    • ++ 自增长主键
    • & 唯一索引
    • * 多值索引 - 数组
    • [A+B] 组合索引或主键
  • 索引数据类型
    • string, number, Date, Array
    • 不能索引 boolean, null, undefined
var db = new Dexie('MyDatabase');
db.version(1).stores({
  friends: '++id,name,shoeSize', // 自增长 PK id
  pets: 'id, name, kind', // 非自增长 PK id
  cars: '++, name', // 自增长 PK, 隐藏
  enemies: ',name,*weaknesses', // 隐藏非自增长 PK
  users: 'meta.ssn, addr.city', // keyPath
  people: '[name+ssn], &ssn', // 组合主键
});
const db = new Dexie('MyDatabase');
db.version(1).stores({
  // friends: '++id, name, age',
  users: '$$uuid,name',
});

// liveQuery 可以 watch 结果
// https://dexie.org/docs/liveQuery()
const friendsObservable = Dexie.liveQuery(() => db.friends.where('age').between(18, 25).toArray());
const subscription = friendsObservable.subscribe({
  next: (result) => console.log('Got result:', JSON.stringify(result)),
  error: (error) => console.error(error),
});
// 触发 liveQuery
await db.friends.add({ name: 'wener', age: 20 });

// dexie-observable
db.on('changes', function (changes) {
  changes.forEach(function (change) {
    switch (change.type) {
      case 1: // CREATED
        console.log('CREATED: ' + JSON.stringify(change.obj));
        break;
      case 2:
        console.log(`UPDATED ${change.key}: ` + JSON.stringify(change.mods));
        break;
      case 3:
        console.log(`DELETED: ` + JSON.stringify(change.oldObj));
        break;
    }
  });
});

Notes​

tip
  • mapToClass, defineClass 可以将数据转为 Class 方便使用
  • Table -> IDBObjectStore
    • hook - creating, reading, updating, deleting
  • Collection
    • Query builder
  • Dexie.Syncable
    • 同步协议

SyncProtocol​

interface ISyncProtocol {
    /** Maximum number of changes per sync() call. Default Infinity. */
    partialsThreshold?: number;

    /** Called by the framework to send changes to server and
     * receive changes back from server. */
    sync (
        context: IPersistedContext,
        url: string,
        options: Object,
        baseRevision: any,
        syncedRevision: any,
        changes: IDatabaseChange[],
        partial: boolean,
        applyRemoteChanges: ApplyRemoteChangesFunction,
        onChangesAccepted: ()=>void,
        onSuccess: (continuation: Continuation)=>void,
        onError: (error: any, again?: number) => void)
    : void;
}