fix: add error state to onAfterDownload

src/bridge.ts

@@ -12,13 +12,14 @@ import { getBinaryExtension } from './platform.js'
 const DENO_VERSION_FILE = 'version.txt'
 const DENO_VERSION_RANGE = '^1.20.3'
 
-type LifecycleHook = () => void | Promise<void>
+type OnBeforeDownloadHook = () => void | Promise<void>
+type OnAfterDownloadHook = (error: Error | null) => void | Promise<void>
 
 interface DenoOptions {
   cacheDirectory?: string
   debug?: boolean
-  onAfterDownload?: LifecycleHook
-  onBeforeDownload?: LifecycleHook
+  onAfterDownload?: OnAfterDownloadHook
+  onBeforeDownload?: OnBeforeDownloadHook
   useGlobal?: boolean
   versionRange?: string
 }
@@ -35,8 +36,8 @@ class DenoBridge {
   cacheDirectory: string
   currentDownload?: ReturnType<DenoBridge['downloadBinary']>
   debug: boolean
-  onAfterDownload?: LifecycleHook
-  onBeforeDownload?: LifecycleHook
+  onAfterDownload?: OnAfterDownloadHook
+  onBeforeDownload?: OnBeforeDownloadHook
   useGlobal: boolean
   versionRange: string
 
@@ -65,13 +66,21 @@ class DenoBridge {
     // a malformed semver range. If this does happen, let's throw an error so
     // that the tests catch it.
     if (downloadedVersion === undefined) {
-      throw new Error('Could not read downloaded binary')
+      const error = new Error(
+        "There was a problem setting up the Edge Functions environment and it's unfortunately not possible to run Edge Functions from this platform. More on supported platforms here: https://deno.land/manual/getting_started/installation.",
+      )
+
+      if (this.onAfterDownload) {
+        this.onAfterDownload(error)
+      }
+
+      throw error
     }
 
     await this.writeVersionFile(downloadedVersion)
 
     if (this.onAfterDownload) {
-      this.onAfterDownload()
+      this.onAfterDownload(null)
     }
 
     return binaryPath
@@ -201,7 +210,8 @@ class DenoBridge {
       ref.ps = ps
     }
   }
+  // eslint-disable-next-line max-lines
 }
 
 export { DenoBridge }
-export type { LifecycleHook, ProcessRef }
+export type { OnAfterDownloadHook, OnBeforeDownloadHook, ProcessRef }

src/bundler.ts

@@ -4,7 +4,7 @@ import { join } from 'path'
 import commonPathPrefix from 'common-path-prefix'
 import { v4 as uuidv4 } from 'uuid'
 
-import { DenoBridge, LifecycleHook } from './bridge.js'
+import { DenoBridge, OnAfterDownloadHook, OnBeforeDownloadHook } from './bridge.js'
 import type { Bundle } from './bundle.js'
 import type { Declaration } from './declaration.js'
 import { FeatureFlags, getFlags } from './feature_flags.js'
@@ -20,8 +20,8 @@ interface BundleOptions {
   distImportMapPath?: string
   featureFlags?: FeatureFlags
   importMaps?: ImportMapFile[]
-  onAfterDownload?: LifecycleHook
-  onBeforeDownload?: LifecycleHook
+  onAfterDownload?: OnAfterDownloadHook
+  onBeforeDownload?: OnBeforeDownloadHook
 }
 
 const bundle = async (

src/server/server.ts

@@ -1,6 +1,6 @@
 import { tmpName } from 'tmp-promise'
 
-import { DenoBridge, LifecycleHook, ProcessRef } from '../bridge.js'
+import { DenoBridge, OnAfterDownloadHook, OnBeforeDownloadHook, ProcessRef } from '../bridge.js'
 import type { EdgeFunction } from '../edge_function.js'
 import { generateStage2 } from '../formats/javascript.js'
 import { ImportMap, ImportMapFile } from '../import_map.js'
@@ -87,8 +87,8 @@ interface ServeOptions {
   distImportMapPath?: string
   inspectSettings?: InspectSettings
   importMaps?: ImportMapFile[]
-  onAfterDownload?: LifecycleHook
-  onBeforeDownload?: LifecycleHook
+  onAfterDownload?: OnAfterDownloadHook
+  onBeforeDownload?: OnBeforeDownloadHook
   formatExportTypeError?: FormatFunction
   formatImportError?: FormatFunction
   port: number