備份一些indexedDB的寫法

    mounted() {
            let request = window.indexedDB.open('tengxiTest', 1)
            let that = this
            request.onerror = function (e) {
                console.log('goes wrong')
                console.log(e)
            }
            request.onsuccess = function (e) {
                console.log('goes along')
                console.log(e.target.result)
                that.dbName = e.target.result
            }
            request.onupgradeneeded = function (e) {
                console.log('version upgrade')
                console.log(e.target.result)
                this.dbName = e.target.result
                let objectStore
                if(!this.dbName.objectStoreNames.contains('fruits')) {
                    objectStore = this.dbName.createObjectStore('fruits', { keyPath: 'id', autoIncrement: true })
                    objectStore.createIndex('name', 'name', { unique: false })
                    objectStore.createIndex('price', 'price', { unique: false })
                    objectStore.createIndex('count', 'count', { unique: false })
                    objectStore.createIndex('fno', 'fno', { unique: false })
                }
            }
    },

addData() {
                console.log('測試')
                console.log(this.dbName)
                let fruitsGroup = [{
                    name: 'Pear',
                    price: 1.12,
                    count: 564,
                    fno: '42483'
                }, {
                    name: 'Orange',
                    price: 5.00,
                    count: 3432,
                    fno: '10938'
                }, {
                    name: 'Grape',
                    price: 8.96,
                    count: 453,
                    fno: '37263'
                }]

                let request = this.dbName.transaction(['fruits'], 'readwrite').objectStore('fruits')
                let result
                fruitsGroup.forEach((item, index) => {
                    console.log('每一項')
                    console.log(item)
                    result = request.add(item)
                })

                result.onsuccess = function (event) {
                    console.log('數據寫入成功')
                }

                result.onerror = function (event) {
                  console.log('數據寫入失敗')
                  console.log(event)
                }
            },

readData (id, callback) {
                let transaction = this.dbName.transaction(['fruits']).objectStore('fruits')
                let request, callbackData
                if(id) {
                    console.log('這裏麼')
                    console.log(id)
                    request = transaction.get(id)
                } else {
                    console.log('走這裏')
                    let index = transaction.index('price')
                    request = index.get(8.96)
                    // request = transaction.getAll()
                }

                request.onerror = function (e) {
                    console.log('讀取數據失敗')
                }
                request.onsuccess = function (e) {
                    if(request.result) {
                        console.log(request.result)
                        callbackData = request.result
                    } else {
                        console.log('白來一趟')
                        callbackData = false
                    }
                    console.log('callback')
                    console.log(callbackData)
                    callback(callbackData)
                }
            },

updateData () {
                this.readData(1, (data) => {
                    let oldData = data
                    console.log('oldData')
                    console.log(oldData)
                    oldData['name'] = 'Pineapple'
                    oldData['price'] = 1.00
                    let transaction = this.dbName.transaction(['fruits'], 'readwrite').objectStore('fruits')
                    let result = transaction.put(oldData)
                    result.onsuccess = function (event) {
                        console.log('數據更新成功')
                    }
                    result.onerror = function (e) {
                        console.log('數據更新失敗')
                    }
                })
            },

deleteData (id) {
                let transaction = this.dbName.transaction(['fruits'], 'readwrite').objectStore('fruits')
                let result = transaction.delete(id)
                result.onsuccess = function (event) {
                    console.log('數據刪除成功')
                }
                result.onerror = function (e) {
                    console.log('數據刪除失敗')
                }
            }