File size: 5,635 Bytes
1e92f2d
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
import { focusManager } from './focusManager'
import { onlineManager } from './onlineManager'
import { pendingThenable } from './thenable'
import { isServer, sleep } from './utils'
import type { CancelOptions, DefaultError, NetworkMode } from './types'

// TYPES

interface RetryerConfig<TData = unknown, TError = DefaultError> {
  fn: () => TData | Promise<TData>
  initialPromise?: Promise<TData>
  abort?: () => void
  onError?: (error: TError) => void
  onSuccess?: (data: TData) => void
  onFail?: (failureCount: number, error: TError) => void
  onPause?: () => void
  onContinue?: () => void
  retry?: RetryValue<TError>
  retryDelay?: RetryDelayValue<TError>
  networkMode: NetworkMode | undefined
  canRun: () => boolean
}

export interface Retryer<TData = unknown> {
  promise: Promise<TData>
  cancel: (cancelOptions?: CancelOptions) => void
  continue: () => Promise<unknown>
  cancelRetry: () => void
  continueRetry: () => void
  canStart: () => boolean
  start: () => Promise<TData>
}

export type RetryValue<TError> = boolean | number | ShouldRetryFunction<TError>

type ShouldRetryFunction<TError = DefaultError> = (
  failureCount: number,
  error: TError,
) => boolean

export type RetryDelayValue<TError> = number | RetryDelayFunction<TError>

type RetryDelayFunction<TError = DefaultError> = (
  failureCount: number,
  error: TError,
) => number

function defaultRetryDelay(failureCount: number) {
  return Math.min(1000 * 2 ** failureCount, 30000)
}

export function canFetch(networkMode: NetworkMode | undefined): boolean {
  return (networkMode ?? 'online') === 'online'
    ? onlineManager.isOnline()
    : true
}

export class CancelledError extends Error {
  revert?: boolean
  silent?: boolean
  constructor(options?: CancelOptions) {
    super('CancelledError')
    this.revert = options?.revert
    this.silent = options?.silent
  }
}

export function isCancelledError(value: any): value is CancelledError {
  return value instanceof CancelledError
}

export function createRetryer<TData = unknown, TError = DefaultError>(
  config: RetryerConfig<TData, TError>,
): Retryer<TData> {
  let isRetryCancelled = false
  let failureCount = 0
  let isResolved = false
  let continueFn: ((value?: unknown) => void) | undefined

  const thenable = pendingThenable<TData>()

  const cancel = (cancelOptions?: CancelOptions): void => {
    if (!isResolved) {
      reject(new CancelledError(cancelOptions))

      config.abort?.()
    }
  }
  const cancelRetry = () => {
    isRetryCancelled = true
  }

  const continueRetry = () => {
    isRetryCancelled = false
  }

  const canContinue = () =>
    focusManager.isFocused() &&
    (config.networkMode === 'always' || onlineManager.isOnline()) &&
    config.canRun()

  const canStart = () => canFetch(config.networkMode) && config.canRun()

  const resolve = (value: any) => {
    if (!isResolved) {
      isResolved = true
      config.onSuccess?.(value)
      continueFn?.()
      thenable.resolve(value)
    }
  }

  const reject = (value: any) => {
    if (!isResolved) {
      isResolved = true
      config.onError?.(value)
      continueFn?.()
      thenable.reject(value)
    }
  }

  const pause = () => {
    return new Promise((continueResolve) => {
      continueFn = (value) => {
        if (isResolved || canContinue()) {
          continueResolve(value)
        }
      }
      config.onPause?.()
    }).then(() => {
      continueFn = undefined
      if (!isResolved) {
        config.onContinue?.()
      }
    })
  }

  // Create loop function
  const run = () => {
    // Do nothing if already resolved
    if (isResolved) {
      return
    }

    let promiseOrValue: any

    // we can re-use config.initialPromise on the first call of run()
    const initialPromise =
      failureCount === 0 ? config.initialPromise : undefined

    // Execute query
    try {
      promiseOrValue = initialPromise ?? config.fn()
    } catch (error) {
      promiseOrValue = Promise.reject(error)
    }

    Promise.resolve(promiseOrValue)
      .then(resolve)
      .catch((error) => {
        // Stop if the fetch is already resolved
        if (isResolved) {
          return
        }

        // Do we need to retry the request?
        const retry = config.retry ?? (isServer ? 0 : 3)
        const retryDelay = config.retryDelay ?? defaultRetryDelay
        const delay =
          typeof retryDelay === 'function'
            ? retryDelay(failureCount, error)
            : retryDelay
        const shouldRetry =
          retry === true ||
          (typeof retry === 'number' && failureCount < retry) ||
          (typeof retry === 'function' && retry(failureCount, error))

        if (isRetryCancelled || !shouldRetry) {
          // We are done if the query does not need to be retried
          reject(error)
          return
        }

        failureCount++

        // Notify on fail
        config.onFail?.(failureCount, error)

        // Delay
        sleep(delay)
          // Pause if the document is not visible or when the device is offline
          .then(() => {
            return canContinue() ? undefined : pause()
          })
          .then(() => {
            if (isRetryCancelled) {
              reject(error)
            } else {
              run()
            }
          })
      })
  }

  return {
    promise: thenable,
    cancel,
    continue: () => {
      continueFn?.()
      return thenable
    },
    cancelRetry,
    continueRetry,
    canStart,
    start: () => {
      // Start loop
      if (canStart()) {
        run()
      } else {
        pause().then(run)
      }
      return thenable
    },
  }
}