feat(utils): 新增 loopUntil 循环调用某个函数直至达到某个条件后返回调用结果

src/utils/index.ts

@@ -48,6 +48,7 @@ export * from './jsonp'
 export * from './keysStrict'
 export * from './loadCss'
 export * from './loadResource'
+export * from './loopUntil'
 export * from './md5'
 export * from './move'
 export * from './omitStrict'

src/utils/loopUntil.test.ts

@@ -0,0 +1,47 @@
+import { loopUntil, LoopUntilRetryLimitExceededError } from './loopUntil'
+
+describe('loopUntil', () => {
+  test('同步正常', async () => {
+    let i = 0
+    const getNumber = () => i++
+    expect(
+      await loopUntil(
+        () => getNumber(),
+        num => num === 10,
+        {
+          retryDelay: 0,
+        },
+      ),
+    ).toBe(10)
+  })
+
+  test('异步正常', async () => {
+    let i = 0
+    const getNumberAsync = async () => i++
+    expect(
+      await loopUntil(
+        () => getNumberAsync(),
+        async num => num === 10,
+        {
+          retryDelay: 0,
+        },
+      ),
+    ).toBe(10)
+  })
+
+  test('重试次数限制', async () => {
+    let i = 0
+    const getNumberAsync = async () => i++
+    await expect(
+      loopUntil(
+        () => getNumberAsync(),
+        num => num === 10,
+        {
+          retryDelay: 0,
+          retryLimit: 5,
+        },
+      ),
+    ).rejects.toBeInstanceOf(LoopUntilRetryLimitExceededError)
+    expect(i).toBe(6)
+  })
+})

src/utils/loopUntil.ts

@@ -0,0 +1,48 @@
+import { AsyncOrSync, OneOrMore } from '../types'
+import { sample } from 'lodash-uni'
+import { wait } from './wait'
+
+export interface LoopUntilOptions {
+  /**
+   * 重试延时，为数组时随机挑选一个。
+   */
+  retryDelay: OneOrMore<number>
+
+  /**
+   * 重试限制。
+   */
+  retryLimit?: number
+}
+
+export class LoopUntilRetryLimitExceededError extends Error {}
+
+/**
+ * 循环调用某个函数直至达到某个条件后返回调用结果。
+ *
+ * @param fn 要调用的函数
+ * @param condition 条件
+ * @param options 选项
+ */
+export async function loopUntil<T>(
+  fn: () => AsyncOrSync<T>,
+  condition: (res: T) => AsyncOrSync<boolean>,
+  options: LoopUntilOptions,
+): Promise<T> {
+  let retryCount = 0
+  // eslint-disable-next-line no-constant-condition
+  while (true) {
+    const res = await fn()
+    if (await condition(res)) {
+      return res
+    }
+    if (options.retryLimit && retryCount >= options.retryLimit) {
+      throw new LoopUntilRetryLimitExceededError('已达到最大重试次数')
+    }
+    retryCount++
+    await wait(
+      typeof options.retryDelay === 'number'
+        ? options.retryDelay
+        : sample(options.retryDelay)!,
+    )
+  }
+}