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    idb-request

    3.2.1 • Public • Published

    idb-request

    Transform IndexedDB request-like object to a Promise.

    Promise is a nice way to deal with primitives of IndexedDB. IDBRequest has onsuccess and onerror callbacks, which perfectly map to Promise's resolve and reject. The same applies to oncomplete and onerror of IDBTransaction.

    If you're going to reuse transactions with Promise syntax, you can't be sure that it will work in all browsers. You need to rely on the default callback syntax or use idb-batch. This issue is well explained in "Tasks, microtasks, queues and schedules" article.

    Internally idb-request fixes IndexedDBShim#204 issue and allows safely iterate over index cursors.

    Installation

    npm install --save idb-request
    

    Example

    Using ES2016 async/await syntax.

    import { open } from 'idb-factory'
    import { request, requestTransaction, requestCursor } from 'idb-request'
    import map from 'lodash.map'
     
    async () => {  
      const db = await open('mydb', 1, upgradeCallback)
      const tr = db.transaction(['books'], 'readwrite')
      const books = tr.objectStore('books')
     
      await Promise.all([
        request(books.put({ id: 1, title: 'Quarry Memories', author: 'Fred' })),
        request(books.put({ id: 2, title: 'Water Buffaloes', author: 'Fred' })),
        request(books.put({ id: 3, title: 'Bedrock Nights', author: 'Barney' })),
        requestTransaction(tr),
      ])
     
      const req = books.index('byAuthor').openCursor(null, 'nextunique') // works everywhere
      const result = []
      await requestCursor(req, (cursor) => {
        result.push(cursor.value)
        cursor.continue()
      })
     
      console.assert(map(result, 'author') === ['Barney', 'Fred'])
    }()
     
    function upgradeCallback(e) {
      const books = e.target.result.createObjectStore('books', { keyPath: 'id' })
      books.createIndex('byTitle', 'title', { unique: true })
      books.createIndex('byAuthor', 'author')
    }

    API

    Each function returns a Promise.

    request(req, [tr])

    Listen to request's onsuccess event.

    import { request } from 'idb-request'
     
    const books = db.transaction(['books'], 'readonly').objectStore('books')
    request(books.count()).then((count) => {})

    Pass the transaction as a second argument to await completion and return the result of the request.

    import { request } from 'idb-request'
     
    const tr = db.transaction(['books'], 'readwrite')
    const books = tr.objectStore('books')
    const req = books.put({ title: 'Store 1' })
     
    request(req, tr).then((requestResult) => {})

    mapCursor(req, iterator)

    Map values over cursor. Iterator has 3 arguments:

    • cursor object,
    • result array, which is returned on resolve. Default value is [].
    • stop resolve promise and exit earlier
    import { mapCursor } from 'idb-request'
     
    const limit = 10
    const result = await mapCursor(books.openCursor(), (cursor, memo, stop) => {
      memo.push(cursor.value)
      if (memo.length >= limit) stop()
      else cursor.continue()
    })

    requestCursor(req, iterator)

    Iterate through object store or index using cursor.

    The same example as mapCursor above:

    import { requestCursor } from 'idb-request'
     
    const limit = 10
    const result = []
    const req = books.openCursor()
     
    await requestCursor(req, (cursor, stop) => {
      result.push(cursor.value)
      if (memo.length >= limit) stop()
      else cursor.continue()
    })
     
    // use result array

    requestTransaction(tr)

    Listen to transaction's oncomplete event.

    import { request, requestTransaction } from 'idb-request'
     
    const tr = db.transaction(['books'], 'readwrite')
    const books = tr.objectStore('books')
     
    await Promise.all([
      request(books.put({ id: 1, title: 'Quarry Memories' })),
      request(books.put({ id: 2, title: 'Water Buffaloes' })),
      request(books.put({ id: 3, title: 'Bedrock Nights' })),
      requestTransaction(tr),
    ])

    License

    MIT

    Install

    npm i idb-request

    DownloadsWeekly Downloads

    10

    Version

    3.2.1

    License

    MIT

    Unpacked Size

    13.5 kB

    Total Files

    6

    Last publish

    Collaborators

    • alekseykulikov