From 76b1b53a4b97fbed9e3992eafa82118fb94828ab Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Fri, 7 Aug 2020 12:56:50 -0400
Subject: [PATCH] refactor(@angular-devkit/build-optimizer): verify Program for
 type-checking passes

---
 .../build_optimizer/src/_golden-api.d.ts          |  4 ++--
 .../src/build-optimizer/build-optimizer.ts        |  3 ++-
 .../src/helpers/transform-javascript.ts           |  8 ++++++--
 .../build_optimizer/src/transforms/scrub-file.ts  | 15 ++++++++++-----
 4 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts b/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts
index 4d3d155545..dadc9fe9b7 100644
--- a/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts
+++ b/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts
@@ -12,9 +12,9 @@ export declare function getPrefixClassesTransformer(): ts.TransformerFactory<ts.
 
 export declare function getPrefixFunctionsTransformer(): ts.TransformerFactory<ts.SourceFile>;
 
-export declare function getScrubFileTransformer(program: ts.Program): ts.TransformerFactory<ts.SourceFile>;
+export declare function getScrubFileTransformer(program?: ts.Program): ts.TransformerFactory<ts.SourceFile>;
 
-export declare function getScrubFileTransformerForCore(program: ts.Program): ts.TransformerFactory<ts.SourceFile>;
+export declare function getScrubFileTransformerForCore(program?: ts.Program): ts.TransformerFactory<ts.SourceFile>;
 
 export declare function getWrapEnumsTransformer(): ts.TransformerFactory<ts.SourceFile>;
 
diff --git a/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer.ts b/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer.ts
index eac95c7f23..1dd9a5572c 100644
--- a/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer.ts
+++ b/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer.ts
@@ -9,6 +9,7 @@ import { readFileSync } from 'fs';
 import {
   TransformJavascriptOptions,
   TransformJavascriptOutput,
+  TransformerFactoryCreator,
   transformJavascript,
 } from '../helpers/transform-javascript';
 import { getPrefixClassesTransformer, testPrefixClasses } from '../transforms/prefix-classes';
@@ -109,7 +110,7 @@ export function buildOptimizer(options: BuildOptimizerOptions): TransformJavascr
   }
 
   // Determine which transforms to apply.
-  const getTransforms = [];
+  const getTransforms: TransformerFactoryCreator[] = [];
 
   let typeCheck = false;
   if (options.isSideEffectFree || originalFilePath && isKnownSideEffectFree(originalFilePath)) {
diff --git a/packages/angular_devkit/build_optimizer/src/helpers/transform-javascript.ts b/packages/angular_devkit/build_optimizer/src/helpers/transform-javascript.ts
index d3e4be4a7c..c50e9d0408 100644
--- a/packages/angular_devkit/build_optimizer/src/helpers/transform-javascript.ts
+++ b/packages/angular_devkit/build_optimizer/src/helpers/transform-javascript.ts
@@ -8,6 +8,9 @@
 import { RawSourceMap } from 'source-map';
 import * as ts from '../../third_party/github.com/Microsoft/TypeScript/lib/typescript';
 
+export type TransformerFactoryCreator = (
+  program?: ts.Program,
+) => ts.TransformerFactory<ts.SourceFile>;
 
 export interface TransformJavascriptOptions {
   content: string;
@@ -16,7 +19,7 @@ export interface TransformJavascriptOptions {
   emitSourceMap?: boolean;
   strict?: boolean;
   typeCheck?: boolean;
-  getTransforms: Array<(program?: ts.Program) => ts.TransformerFactory<ts.SourceFile>>;
+  getTransforms: TransformerFactoryCreator[];
 }
 
 export interface TransformJavascriptOutput {
@@ -110,7 +113,8 @@ export function transformJavascript(
       };
     }
 
-    const transforms = getTransforms.map((getTf) => getTf(undefined));
+    // All fast path transformers do not use a program
+    const transforms = getTransforms.map((getTf) => getTf(/* program */ undefined));
 
     const result = ts.transform(tempSourceFile, transforms, tsOptions);
     if (result.transformed.length === 0 || result.transformed[0] === tempSourceFile) {
diff --git a/packages/angular_devkit/build_optimizer/src/transforms/scrub-file.ts b/packages/angular_devkit/build_optimizer/src/transforms/scrub-file.ts
index bc213449db..7e8d89af14 100644
--- a/packages/angular_devkit/build_optimizer/src/transforms/scrub-file.ts
+++ b/packages/angular_devkit/build_optimizer/src/transforms/scrub-file.ts
@@ -20,17 +20,22 @@ export function testScrubFile(content: string) {
   return markers.some((marker) => content.indexOf(marker) !== -1);
 }
 
-export function getScrubFileTransformer(program: ts.Program): ts.TransformerFactory<ts.SourceFile> {
-  return scrubFileTransformer(program.getTypeChecker(), false);
+export function getScrubFileTransformer(program?: ts.Program): ts.TransformerFactory<ts.SourceFile> {
+  return scrubFileTransformer(program, false);
 }
 
 export function getScrubFileTransformerForCore(
-  program: ts.Program,
+  program?: ts.Program,
 ): ts.TransformerFactory<ts.SourceFile> {
-  return scrubFileTransformer(program.getTypeChecker(), true);
+  return scrubFileTransformer(program, true);
 }
 
-function scrubFileTransformer(checker: ts.TypeChecker, isAngularCoreFile: boolean) {
+function scrubFileTransformer(program: ts.Program | undefined, isAngularCoreFile: boolean) {
+  if (!program) {
+    throw new Error('scrubFileTransformer requires a TypeScript Program.');
+  }
+  const checker = program.getTypeChecker();
+
   return (context: ts.TransformationContext): ts.Transformer<ts.SourceFile> => {
 
     const transformer: ts.Transformer<ts.SourceFile> = (sf: ts.SourceFile) => {