Add type checking events (vercel#24595)

Will send events like this:

```
[telemetry] {
  "eventName": "NEXT_TYPE_CHECK_COMPLETED",
  "payload": {
    "durationInSeconds": 2,
    "typescriptVersion": "3.8.3",
    "inputFilesCount": 16,
    "totalFilesCount": 289,
    "incremental": false
  }
}
```

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.

## Documentation / Examples

- [ ] Make sure the linting passes

packages/next/build/index.ts

@@ -66,6 +66,7 @@ import {
   eventBuildOptimize,
   eventCliSession,
   eventNextPlugins,
+  eventTypeCheckCompleted,
 } from '../telemetry/events'
 import { Telemetry } from '../telemetry/storage'
 import { CompilerResult, runCompiler } from './compiler'
@@ -158,10 +159,6 @@ export default async function build(
       }
     }
 
-    const typeCheckingSpinner = createSpinner({
-      prefixText: `${Log.prefixes.info} Checking validity of types`,
-    })
-
     const telemetry = new Telemetry({ distDir })
     setGlobal('telemetry', telemetry)
 
@@ -184,12 +181,29 @@ export default async function build(
     )
 
     const ignoreTypeScriptErrors = Boolean(config.typescript?.ignoreBuildErrors)
-    await nextBuildSpan
+    const typeCheckStart = process.hrtime()
+    const typeCheckingSpinner = createSpinner({
+      prefixText: `${Log.prefixes.info} Checking validity of types`,
+    })
+
+    const verifyResult = await nextBuildSpan
       .traceChild('verify-typescript-setup')
       .traceAsyncFn(() =>
         verifyTypeScriptSetup(dir, pagesDir, !ignoreTypeScriptErrors)
       )
 
+    const typeCheckEnd = process.hrtime(typeCheckStart)
+
+    telemetry.record(
+      eventTypeCheckCompleted({
+        durationInSeconds: typeCheckEnd[0],
+        typescriptVersion: verifyResult.version,
+        inputFilesCount: verifyResult.result?.inputFilesCount,
+        totalFilesCount: verifyResult.result?.totalFilesCount,
+        incremental: verifyResult.result?.incremental,
+      })
+    )
+
     if (typeCheckingSpinner) {
       typeCheckingSpinner.stopAndPersist()
     }

packages/next/export/worker.ts

@@ -50,7 +50,7 @@ interface ExportPageInput {
   subFolders?: boolean
   serverless: boolean
   optimizeFonts: boolean
-  optimizeImages: boolean
+  optimizeImages?: boolean
   optimizeCss: any
   parentSpanId: any
 }

packages/next/lib/typescript/runTypeCheck.ts

@@ -10,6 +10,9 @@ import { CompileError } from '../compile-error'
 export interface TypeCheckResult {
   hasWarnings: boolean
   warnings?: string[]
+  inputFilesCount: number
+  totalFilesCount: number
+  incremental: boolean
 }
 
 export async function runTypeCheck(
@@ -23,7 +26,12 @@ export async function runTypeCheck(
   )
 
   if (effectiveConfiguration.fileNames.length < 1) {
-    return { hasWarnings: false }
+    return {
+      hasWarnings: false,
+      inputFilesCount: 0,
+      totalFilesCount: 0,
+      incremental: false,
+    }
   }
   const requiredConfig = getRequiredConfiguration(ts)
 
@@ -66,5 +74,11 @@ export async function runTypeCheck(
       .filter((d) => d.category === DiagnosticCategory.Warning)
       .map((d) => getFormattedDiagnostic(ts, baseDir, d))
   )
-  return { hasWarnings: true, warnings }
+  return {
+    hasWarnings: true,
+    warnings,
+    inputFilesCount: effectiveConfiguration.fileNames.length,
+    totalFilesCount: program.getSourceFiles().length,
+    incremental: false,
+  }
 }

packages/next/lib/verifyTypeScriptSetup.ts

@@ -16,14 +16,14 @@ export async function verifyTypeScriptSetup(
   dir: string,
   pagesDir: string,
   typeCheckPreflight: boolean
-): Promise<TypeCheckResult | boolean> {
+): Promise<{ result?: TypeCheckResult; version: string | null }> {
   const tsConfigPath = path.join(dir, 'tsconfig.json')
 
   try {
     // Check if the project uses TypeScript:
     const intent = await getTypeScriptIntent(dir, pagesDir)
     if (!intent) {
-      return false
+      return { version: null }
     }
     const firstTimeSetup = intent.firstTimeSetup
 
@@ -43,13 +43,14 @@ export async function verifyTypeScriptSetup(
     // Next.js' types:
     await writeAppTypeDeclarations(dir)
 
+    let result
     if (typeCheckPreflight) {
       const { runTypeCheck } = require('./typescript/runTypeCheck')
 
       // Verify the project passes type-checking before we go to webpack phase:
-      return await runTypeCheck(ts, dir, tsConfigPath)
+      result = await runTypeCheck(ts, dir, tsConfigPath)
     }
-    return true
+    return { result, version: ts.version }
   } catch (err) {
     // These are special errors that should not show a stack trace:
     if (err instanceof CompileError) {

packages/next/telemetry/events/build.ts

@@ -2,7 +2,25 @@ const REGEXP_DIRECTORY_DUNDER = /[\\/]__[^\\/]+(?<![\\/]__(?:tests|mocks))__[\\/
 const REGEXP_DIRECTORY_TESTS = /[\\/]__(tests|mocks)__[\\/]/i
 const REGEXP_FILE_TEST = /\.(?:spec|test)\.[^.]+$/i
 
-const EVENT_BUILD_DURATION = 'NEXT_BUILD_COMPLETED'
+const EVENT_TYPE_CHECK_COMPLETED = 'NEXT_TYPE_CHECK_COMPLETED'
+type EventTypeCheckCompleted = {
+  durationInSeconds: number
+  typescriptVersion: string | null
+  inputFilesCount?: number
+  totalFilesCount?: number
+  incremental?: boolean
+}
+
+export function eventTypeCheckCompleted(
+  event: EventTypeCheckCompleted
+): { eventName: string; payload: EventTypeCheckCompleted } {
+  return {
+    eventName: EVENT_TYPE_CHECK_COMPLETED,
+    payload: event,
+  }
+}
+
+const EVENT_BUILD_COMPLETED = 'NEXT_BUILD_COMPLETED'
 type EventBuildCompleted = {
   durationInSeconds: number
   totalPageCount: number
@@ -18,7 +36,7 @@ export function eventBuildCompleted(
   >
 ): { eventName: string; payload: EventBuildCompleted } {
   return {
-    eventName: EVENT_BUILD_DURATION,
+    eventName: EVENT_BUILD_COMPLETED,
     payload: {
       ...event,
       totalPageCount: pagePaths.length,
@@ -33,7 +51,7 @@ export function eventBuildCompleted(
   }
 }
 
-const EVENT_BUILD_OPTIMIZE = 'NEXT_BUILD_OPTIMIZED'
+const EVENT_BUILD_OPTIMIZED = 'NEXT_BUILD_OPTIMIZED'
 type EventBuildOptimized = {
   durationInSeconds: number
   totalPageCount: number
@@ -61,7 +79,7 @@ export function eventBuildOptimize(
   >
 ): { eventName: string; payload: EventBuildOptimized } {
   return {
-    eventName: EVENT_BUILD_OPTIMIZE,
+    eventName: EVENT_BUILD_OPTIMIZED,
     payload: {
       ...event,
       totalPageCount: pagePaths.length,

packages/next/telemetry/trace/trace.ts

@@ -71,7 +71,7 @@ export class Span {
     }
   }
 
-  async traceAsyncFn(fn: any) {
+  async traceAsyncFn<T>(fn: () => T | Promise<T>): Promise<T> {
     try {
       return await fn()
     } finally {