javascript - 解决未在递归 Promise 函数中调用的问题

Question

我做了一个递归函数来实现 incremental synchronization of Google Calendar Events list使用他们的 JavaScript API，除了 resolve() 之外，一切似乎都正常，我不明白为什么......

我错过了什么？

  syncEvents (calendarId) {

      let eventsItems = []
      let syncToken = null
      let pageToken = null

      function next(params) {
        return new Promise((resolve) => {
          gapi.client.calendar.events.list( params ).then( (response) => {
            syncToken = response.result.nextSyncToken;
            pageToken = response.result.nextPageToken;

            let items = response.result.items
            eventsItems.push(items)

            if (pageToken) {
              return next({
                'calendarId': params.calendarId,
                'pageToken': pageToken,
                'syncToken': syncToken
              })
            }
            if (syncToken) {
              console.log('ok now resolve!') // <= This is called...
              resolve(response)
            }

          })
        })

      }

      next({'calendarId': calendarId}).then( (result) => {
          console.log(eventsItems) // <= And this is not called...
      })

  }

谢谢!

Answer 1

如果我可以尝试使用一些新的异步/等待糖，那么你不需要任何递归函数:)

async syncEvents(calendarId) {
  const eventsItems = []
  const query = {calendarId}

  while (true) {
    const response = await gapi.client.calendar.events.list(query)
    const {nextSyncToken, nextPageToken, items} = response.result

    eventsItems.push(items)

    if (nextPageToken) {
      query.pageToken = nextPageToken,
      query.syncToken = nextSyncToken
    } else {
      return eventsItems
    }
  }
}