const dbName = "test";
const dbVersion = 1;export default {// indexedDB兼容
  indexedDB:window.indexedDB ||window.webkitindexedDB ||window.msIndexedDB ||window.mozIndexedDB,//name:表名  key:主键 ,cursorIndex 索引
  store: {teacher: {name: "teacher",key: "id",cursorIndex: [{ name: "teachNum", unique: false }]},student: {name: "student",key: "id",cursorIndex: [{ name: "stuNum", unique: false }]}},async initDB() {let that = this;let request = this.indexedDB.open(dbName, dbVersion);request.onerror = function() {console.log("打开数据库失败");};request.onsuccess = function() {console.log("打开数据库成功");};request.onupgradeneeded = function(event) {let db = event.target.result;for (var t in that.store) {if (!db.objectStoreNames.contains(that.store[t].name)) {var objectStore = db.createObjectStore(that.store[t].name, {keyPath: that.store[t].key,autoIncrement: true});for (let i = 0; i < that.store[t].cursorIndex.length; i++) {const element = that.store[t].cursorIndex[i];objectStore.createIndex(element.name, element.name, {unique: element.unique});}}}};},// 打开数据库openDB: function() {return new Promise((resolve, reject) => {let request = this.indexedDB.open(dbName, dbVersion);request.onerror = function(event) {reject("IndexedDB数据库打开错误，" + event);};request.onsuccess = function(event) {resolve(event.target.result);};});},// 删除表deleteDB: function(table) {let deleteQuest = this.indexedDB.deleteDatabase(table);deleteQuest.onerror = function() {return Promise.resolve(false);};deleteQuest.onsuccess = function() {return Promise.resolve(true);};},// 关闭数据库closeDB: async function(db) {try {let d;if (!db) {d = await this.openDB();}let closeQuest = d.closeDB();return new Promise(resolve => {closeQuest.onerror = function() {resolve(false);};closeQuest.onsuccess = function() {resolve(true);};});} catch (error) {return Promise.resolve(false);}},// 添加数据，add添加新值insert: async function(table, data) {try {let db = await this.openDB();let request = db.transaction(table.name, "readwrite").objectStore(table.name).add(data);return new Promise((resolve, reject) => {request.onerror = function() {reject("添加数据出错");};request.onsuccess = function() {resolve(true);};});} catch (error) {console.log(error);return Promise.resolve(false);}},// 更新update: async function(table, data) {try {let db = await this.openDB();let request = db.transaction(table.name, "readwrite").objectStore(table.name).put(data);return new Promise(resolve => {request.onerror = function() {resolve(false);};request.onsuccess = function() {resolve(true);};});} catch (error) {return Promise.resolve(false);}},// 删除数据delete: async function(table, keyValue) {try {let db = await this.openDB();let request = db.transaction(table.name, "readwrite").objectStore(table.name).delete(keyValue);return new Promise(resolve => {request.onerror = function() {resolve(false);};request.onsuccess = function() {resolve(true);};});} catch (error) {return Promise.resolve(false);}},// 清空数据clear: async function(table) {let db = await this.openDB();let store = db.transaction(table.name, "readwrite").objectStore(table.name);store.clear();},// 查询数据 表名 索引值 索引 key  没有value key为key 而不是索引get: async function(table, keyValue, indexCursor) {try {let db = await this.openDB();let store = db.transaction(table.name, "readonly").objectStore(table.name);let request;request = !keyValue? store.openCursor(): indexCursor? store.index(indexCursor).get(keyValue): store.get(keyValue);let data = [];return new Promise(resolve => {request.onerror = function() {resolve("查询数据失败");};request.onsuccess = function(event) {if (!keyValue && !indexCursor) {if (event.target.result) {data.push(event.target.result.value);event.target.result.continue();} else {resolve(data);}} else {resolve([event.target.result]);}};});} catch (error) {return Promise.reject(error);}},//   通过游标操作数据, callback中要有游标移动方式handleDataByCursor: async function(table, keyRange) {try {let kRange = keyRange || "";let db = await this.openDB();let store = db.transaction(table, "readwrite").objectStore(table),request;request = store.openCursor(kRange);return new Promise(resolve => {request.onerror = function() {resolve("通过游标获取数据报错");};request.onsuccess = function(event) {let cursor = event.target.result;resolve(cursor);};});} catch (error) {return Promise.reject(error);}},// 通过索引游标操作数据, callback中要有游标移动方式handleDataByIndex: async function(table, keyRange, sursorIndex) {try {let kRange = keyRange || "";let db = await this.openDB();let store = db.transaction(table, "readwrite").objectStore(table),request;request = store.index(sursorIndex).openCursor(kRange);return new Promise(resolve => {request.onerror = function() {resolve("通过索引游标获取数据报错");};request.onsuccess = function(event) {let cursor = event.target.result;if (cursor) {resolve(cursor);}};});} catch (error) {return Promise.reject(error);}},// 创建游标索引createCursorIndex: async function(table, cursorIndex, unique) {var db = await this.openDB();let store = db.transaction(table, "readwrite").objectStore(table);store.createIndex(cursorIndex, cursorIndex, {unique: unique});return Promise.resolve();}
};