resolveAsyncComponent() — vue Function Reference

Architecture documentation for the resolveAsyncComponent() function in resolve-async-component.ts from the vue codebase.

Function typescript CoreRuntime GlobalAPI calls 1

Entity Profile

CoreRuntime→ GlobalAPI→ resolveAsyncComponent() — vue Function Reference

Dependency Diagram

graph TD
  8c441611_2116_3c97_0a3e_745f6b67f979["resolveAsyncComponent()"]
  dd72f8e2_44a1_1e0f_8728_ea1860ede92f["ensureCtor()"]
  8c441611_2116_3c97_0a3e_745f6b67f979 -->|calls| dd72f8e2_44a1_1e0f_8728_ea1860ede92f
  style 8c441611_2116_3c97_0a3e_745f6b67f979 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

src/core/vdom/helpers/resolve-async-component.ts lines 38–157

export function resolveAsyncComponent(
  factory: { (...args: any[]): any; [keye: string]: any },
  baseCtor: typeof Component
): typeof Component | void {
  if (isTrue(factory.error) && isDef(factory.errorComp)) {
    return factory.errorComp
  }

  if (isDef(factory.resolved)) {
    return factory.resolved
  }

  const owner = currentRenderingInstance
  if (owner && isDef(factory.owners) && factory.owners.indexOf(owner) === -1) {
    // already pending
    factory.owners.push(owner)
  }

  if (isTrue(factory.loading) && isDef(factory.loadingComp)) {
    return factory.loadingComp
  }

  if (owner && !isDef(factory.owners)) {
    const owners = (factory.owners = [owner])
    let sync = true
    let timerLoading: number | null = null
    let timerTimeout: number | null = null

    owner.$on('hook:destroyed', () => remove(owners, owner))

    const forceRender = (renderCompleted: boolean) => {
      for (let i = 0, l = owners.length; i < l; i++) {
        owners[i].$forceUpdate()
      }

      if (renderCompleted) {
        owners.length = 0
        if (timerLoading !== null) {
          clearTimeout(timerLoading)
          timerLoading = null
        }
        if (timerTimeout !== null) {
          clearTimeout(timerTimeout)
          timerTimeout = null
        }
      }
    }

    const resolve = once((res: Object | Component) => {
      // cache resolved
      factory.resolved = ensureCtor(res, baseCtor)
      // invoke callbacks only if this is not a synchronous resolve
      // (async resolves are shimmed as synchronous during SSR)
      if (!sync) {
        forceRender(true)
      } else {
        owners.length = 0
      }
    })

    const reject = once(reason => {
      __DEV__ &&
        warn(
          `Failed to resolve async component: ${String(factory)}` +
            (reason ? `\nReason: ${reason}` : '')
        )
      if (isDef(factory.errorComp)) {
        factory.error = true
        forceRender(true)
      }
    })

    const res = factory(resolve, reject)

    if (isObject(res)) {
      if (isPromise(res)) {
        // () => Promise
        if (isUndef(factory.resolved)) {
          res.then(resolve, reject)
        }
      } else if (isPromise(res.component)) {
        res.component.then(resolve, reject)

        if (isDef(res.error)) {
          factory.errorComp = ensureCtor(res.error, baseCtor)
        }

        if (isDef(res.loading)) {
          factory.loadingComp = ensureCtor(res.loading, baseCtor)
          if (res.delay === 0) {
            factory.loading = true
          } else {
            // @ts-expect-error NodeJS timeout type
            timerLoading = setTimeout(() => {
              timerLoading = null
              if (isUndef(factory.resolved) && isUndef(factory.error)) {
                factory.loading = true
                forceRender(false)
              }
            }, res.delay || 200)
          }
        }

        if (isDef(res.timeout)) {
          // @ts-expect-error NodeJS timeout type
          timerTimeout = setTimeout(() => {
            timerTimeout = null
            if (isUndef(factory.resolved)) {
              reject(__DEV__ ? `timeout (${res.timeout}ms)` : null)
            }
          }, res.timeout)
        }
      }
    }

    sync = false
    // return in case resolved synchronously
    return factory.loading ? factory.loadingComp : factory.resolved
  }
}