indexeddb

Getting data inside a google Chrome IndexedDB from Bash or Python

由 亡梦爱人 提交于 2020-06-28 04:20:34
问题 I have LevelDB (IndexedDB) file from my Google Chrome, the file is located in this folder: /home/<user>/.config/google-chrome/Default/IndexedDB/https_<site>_0.indexeddb.leveldb/ The folder content is: $ ls 000005.ldb 000006.log CURRENT LOCK LOG MANIFEST-000001 And I have a very simple python script for opening it: #!/bin/python import leveldb db = leveldb.LevelDB('./000005.ldb') Now I always get this error: leveldb.LevelDBError: IO error: ./000005.ldb/LOCK: Not a directory Does anyone have

get GroupBy count in Dexie

由 隐身守侯 提交于 2020-05-15 08:11:57
问题 I have an IndexedDB table that follows accepts following structured JSON as a row: { id : 1, name : 'doc1', createdDate : '2018-08-08' } I want to get count for each available date in the table. ie: groupby:date then count . Expected example output is in the format of: { '2018-08-08' : 5, '2018-08-18' : 19, ... } Table contains large number of records. So, how can efficiently achieve this requirement using Dexie? 回答1: If you index createdDate, const db = new Dexie("yourDB"); db.version(1)

Multiple keys query in IndexedDB (Similar to OR in sql)

由 我只是一个虾纸丫 提交于 2020-05-13 07:56:10
问题 I have store with multiEntry index on tags. { tags: [ 'tag1', 'tag2', 'tag3' ] } And i have query that also list of tags. [ 'tag2', 'tag1', 'tag4' ] I need to get all records which contain one of tag in query (Similar to SQL OR statement). Currently I cannot find any other solution except iterate over tags in query and search by the each tag in the store. Is there any better solution? Thank you. 回答1: You cannot retrieve all results with one query except with iteration. You can optimize the

Why are indexedDB requests made before the event handlers are declared?

由 江枫思渺然 提交于 2020-05-13 07:07:59
问题 It feels like this must be a stupid question but I don't understand something fundamental about making a request in indexedDB. Why are the requests made before the event handlers are defined? For example, the request = objectStore.add(data) is made before the request.onsuccess and request.onerror functions are declared. Is this correct? Is it possible that the request could complete before the event handlers are registered? I'm comparing it to the creation of an image element, followed by

Why are indexedDB requests made before the event handlers are declared?

由 二次信任 提交于 2020-05-13 07:04:06
问题 It feels like this must be a stupid question but I don't understand something fundamental about making a request in indexedDB. Why are the requests made before the event handlers are defined? For example, the request = objectStore.add(data) is made before the request.onsuccess and request.onerror functions are declared. Is this correct? Is it possible that the request could complete before the event handlers are registered? I'm comparing it to the creation of an image element, followed by

在JavaScript中使用ES6 Proxy做类型安全

由 家住魔仙堡 提交于 2020-04-29 15:22:38
当前，大多数解决 JavaScript 中类型安全不足的解决方案都是基于静态类型检查和类型推断。 TypeScript 和 Flow 通过添加静态类型注释来拓展 JavaScript ，并且可以在编译时验证您的代码，并使用相同的抽象语法树来输出最终的JS代码。由于 IDE 可以依靠静态分析来提供自动完成和开发辅助，因此，这对于改善开发人员的体验非常有效。但是，关于类型安全，仍然存在一个主要缺陷： 一旦使用 JavaScript 进行编译并在浏览器中运行，就不再保证所使用的变量具有预期的类型。 欺骗 TypeScript 非常容易。基本上，任何可以避免静态分析的操作都可能在不通知 TypeScript 的情况下潜在的更改变量的类型： 使用方括号和一个代表属性的变量来检索属性 通过 HTML 事件属性， setTimeout 或 Function 构造函数进行动态代码评估 全局变量与外部库或浏览器扩展冲突 一个内置原型，该原型已被库或polyfill意外修改、 TypeScript 开发人员试图避免上面的这些模式，并认为这是最佳实践。但是，由于开发人员对静态类型系统的信任，这可能导致一些混乱的问题，而忘记了它实际上最终是在计算机上运行的动态脚本语言。 JS 中还有另一种类型安全的方法被遗忘了，可能值得更多关注： JavaScript 本身中的强类型检查。 由于 ECMAScript5

Order of promise array in Promise.allSettled and order in which database transactions are created?

由 北战南征 提交于 2020-04-15 14:54:53
问题 In the following code, Promise.allSettled( [ entry_save(), save_state(), get_HTML() ] ).then( ... ); promises entry_save and save_state are both readwrite database transactions and get_HTML is readonly . The two readwrite transactions could be combined together but that complicates the undo/redo chain that is maintained and it ties the success and rollback of the two together which is undesired. The entry_save transaction needs to write before the save_state transaction. Before moving entry

Order of promise array in Promise.allSettled and order in which database transactions are created?

由 落花浮王杯 提交于 2020-04-15 14:54:49
问题 In the following code, Promise.allSettled( [ entry_save(), save_state(), get_HTML() ] ).then( ... ); promises entry_save and save_state are both readwrite database transactions and get_HTML is readonly . The two readwrite transactions could be combined together but that complicates the undo/redo chain that is maintained and it ties the success and rollback of the two together which is undesired. The entry_save transaction needs to write before the save_state transaction. Before moving entry

Order of promise array in Promise.allSettled and order in which database transactions are created?

由 烈酒焚心 提交于 2020-04-15 14:53:09
问题 In the following code, Promise.allSettled( [ entry_save(), save_state(), get_HTML() ] ).then( ... ); promises entry_save and save_state are both readwrite database transactions and get_HTML is readonly . The two readwrite transactions could be combined together but that complicates the undo/redo chain that is maintained and it ties the success and rollback of the two together which is undesired. The entry_save transaction needs to write before the save_state transaction. Before moving entry

JS对象—2.工具对象(存储)

由 ↘锁芯ラ 提交于 2020-04-11 16:15:26
一 . localStorage本地存储对象 , sessionStorage会话存储 对象 静态方法 setItem ( "key" , "value" ) 设置数据 getItem ( "key" ) 获取数据 removeItem ( "key" ) 删除数据 clear ( ) 清空所有数据 key ( index ) 根据序号获取数据键名 length 存储数据数量 二 . cookie : 见document对象 三 . applicationCache离线存储对象 事件属性 onchecking : 开始检查更新 ondownloading : 开始下载资源 onprogress : 每下一个资源触发一次 onupdateready : 更新完成事件 ( 页面先使用了离线的 , 更新完成后需要手动刷新一次 ) onnoupdate : 无需更新事件 五 . web数据库 ( 1 ) Web SQL 只有Chrome , Safai , Opera支持 , 估计会废弃 ( 2 ) IndexedDB 只有Chrome , Firefox支持 六 . requestFileSystem 文件系统 只有Chrome支持 , 不稳定 , 而且好像也没什么使用场景 来源： oschina 链接： https://my.oschina.net/u/4331414/blog
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