CustomPrecacheController.ts

import { CleanupResult, InstallResult, PrecacheController } from "workbox-precaching"

export class CustomPrecacheController extends PrecacheController {

  private _debugPrint = false

  private _isPrecaching = false
  get isPrecaching() { return this._isPrecaching }

  private _installResult: InstallResult = undefined
  get installResult() { return this._installResult }

  private _cleanupResult: CleanupResult = undefined
  get cleanupResult() { return this._cleanupResult }

  constructor(
    readonly appCacheKey: string,
    ...options: ConstructorParameters<typeof PrecacheController>
  ) {
    super(...options)
  }

  enableDebugPrint(enable = true) {
    this._debugPrint = enable
    return this
  }

  override async install(event: ExtendableEvent) {
    this._isPrecaching = true
    this._installResult = await super.install(event)
    this._isPrecaching = false

    if (this._debugPrint) {
      this.printInstallResult()
    }
    return this._installResult
  }

  override async activate(event: ExtendableEvent) {
    this._cleanupResult = await super.activate(event)

    if (this._debugPrint) {
      this.printCleanupResult()
    }
    return this._cleanupResult
  }

  printInstallResult() {
    const header = `===== SW ${this.appCacheKey} (Install) =====`
    const footer = "".padEnd(header.length, "=")

    const lines = [
      header,
      ...(
        this._installResult?.updatedURLs?.length > 0
          ? this._installResult.updatedURLs.map(req => `>> ${req}`)
          : [`>> NO INSTALL RESULT <<`]
      ),
      footer,
    ]

    console.debug(lines.join("\n"), this)
  }

  printCleanupResult() {
    const header = `===== SW ${this.appCacheKey} (Cleanup) =====`
    const footer = "".padEnd(header.length, "=")

    const lines = [
      header,
      ...(
        this._cleanupResult?.deletedCacheRequests?.length > 0
          ? this._cleanupResult.deletedCacheRequests.map(req => `>> ${req}`)
          : [`>> NO CLEANUP RESULT <<`]
      ),
      footer,
    ]

    console.debug(lines.join("\n"), this)
  }
}