small refactoring

Author: tbosch

src/transformer.ts

@@ -15,7 +15,7 @@ import * as es5processor from './es5processor';
 import {ModulesManifest} from './modules_manifest';
 import {containsInlineSourceMap, extractInlineSourceMap, parseSourceMap, removeInlineSourceMap, setInlineSourceMap, SourceMapper, SourcePosition} from './source_map_utils';
 import {createTransformerFromSourceMap} from './transformer_sourcemap';
-import {createOriginalNodeTypeChecker, firstTransform, lastTransform, preTypeScriptTransform} from './transformer_util';
+import {createCustomTransformers, createOriginalNodeTypeChecker} from './transformer_util';
 import * as tsickle from './tsickle';
 
 export interface TransformerOptions extends es5processor.Es5ProcessorOptions, tsickle.Options {
@@ -117,11 +117,10 @@ export function emitWithTsickle(
       afterTsTransformers.push(...customTransformers.afterTs);
     }
   }
-
-  // add transformers that have a fixed positions
-  beforeTsTransformers.unshift(firstTransform);
-  beforeTsTransformers.push(preTypeScriptTransform);
-  afterTsTransformers.push(lastTransform);
+  customTransformers = createCustomTransformers({
+    before: beforeTsTransformers.map(tf => skipTransformForSourceFileIfNeeded(host, tf)),
+    after: afterTsTransformers.map(tf => skipTransformForSourceFileIfNeeded(host, tf))
+  });
 
   const writeFileDelegate = writeFile || tsHost.writeFile.bind(tsHost);
   const modulesManifest = new ModulesManifest();
@@ -142,11 +141,8 @@ export function emitWithTsickle(
         writeFileDelegate(fileName, content, writeByteOrderMark, onError, sourceFiles);
       };
 
-  const {diagnostics: tsDiagnostics, emitSkipped, emittedFiles} =
-      program.emit(targetSourceFile, writeFileImpl, cancellationToken, emitOnlyDtsFiles, {
-        before: beforeTsTransformers.map(tf => skipTransformForSourceFileIfNeeded(host, tf)),
-        after: afterTsTransformers.map(tf => skipTransformForSourceFileIfNeeded(host, tf))
-      });
+  const {diagnostics: tsDiagnostics, emitSkipped, emittedFiles} = program.emit(
+      targetSourceFile, writeFileImpl, cancellationToken, emitOnlyDtsFiles, customTransformers);
 
   const externs: {[fileName: string]: string} = {};
   if (options.transformTypesToClosure) {

src/transformer_sourcemap.ts

@@ -36,12 +36,9 @@ export function createTransformerFromSourceMap(
       //    regarding comment synthesization
       // - types: as they are not emited anyways
       //          and it leads to errors with `extends` cases.
-      if (originalNode && (
-          isLiteralKind(node.kind) ||
-          node.kind === ts.SyntaxKind.Identifier ||
-          isTypeNodeKind(node.kind) ||
-          node.kind === ts.SyntaxKind.IndexSignature
-          )) {
+      if (originalNode &&
+          (isLiteralKind(node.kind) || node.kind === ts.SyntaxKind.Identifier ||
+           isTypeNodeKind(node.kind) || node.kind === ts.SyntaxKind.IndexSignature)) {
         return originalNode;
       }
       node = visitEachChild(node, visitNode, context);

src/transformer_util.ts

@@ -9,10 +9,27 @@
 import * as ts from 'typescript';
 import * as tsickle from './tsickle';
 
+/**
+ * Adjusts the given CustomTransformers with additional transformers
+ * to fix bugs in TypeScript.
+ * @param given A
+ */
+export function createCustomTransformers(given: ts.CustomTransformers): ts.CustomTransformers {
+  if (!given.after && !given.before) {
+    return given;
+  }
+  const before = given.before || [];
+  before.unshift(firstTransform);
+  before.push(preTypeScriptTransform);
+  const after = given.after || [];
+  after.unshift(postTypescriptTransform);
+  return {before, after};
+}
+
 /**
  * Transform to be used as first transform to reset some state.
  */
-export function firstTransform(context: ts.TransformationContext) {
+function firstTransform(context: ts.TransformationContext) {
   return (sourceFile: ts.SourceFile) => {
     (context as TransformationContext).fileContext = new FileContext(sourceFile);
     return sourceFile;
@@ -58,7 +75,7 @@ class FileContext {
  *
  * This prepares the node tree to workaround some bugs in the TypeScript emitter.
  */
-export function preTypeScriptTransform(context: ts.TransformationContext) {
+function preTypeScriptTransform(context: ts.TransformationContext) {
   return (sourceFile: ts.SourceFile) => {
     const fileCtx = assertFileContext(context, sourceFile);
 
@@ -118,7 +135,7 @@ export function preTypeScriptTransform(context: ts.TransformationContext) {
  * This fixes places where the TypeScript transformer does not
  * emit synthetic comments.
  */
-export function lastTransform(context: ts.TransformationContext) {
+function postTypescriptTransform(context: ts.TransformationContext) {
   return (sourceFile: ts.SourceFile) => {
     const fileContext = assertFileContext(context, sourceFile);
     const nodePath: ts.Node[] = [];

test/transformer_util_test.ts

@@ -9,7 +9,7 @@
 import {expect} from 'chai';
 import * as ts from 'typescript';
 
-import {firstTransform, lastTransform, preTypeScriptTransform, visitEachChild, visitNodeWithSynthesizedComments} from '../src/transformer_util';
+import {createCustomTransformers, visitEachChild, visitNodeWithSynthesizedComments} from '../src/transformer_util';
 
 import * as testSupport from './test_support';
 
@@ -20,10 +20,7 @@ describe('transformer util', () => {
       tsSources: {[fileName: string]: string},
       transform: ts.TransformerFactory<ts.SourceFile>): {[fileName: string]: string} {
     const {program, host} = testSupport.createProgramAndHost(objectToMap(tsSources));
-    const transformers: ts.CustomTransformers = {
-      before: [firstTransform, transform, preTypeScriptTransform],
-      after: [lastTransform]
-    };
+    const transformers = createCustomTransformers({before: [transform]});
     const jsSources: {[fileName: string]: string} = {};
     program.emit(undefined, (fileName: string, data: string) => {
       jsSources[fileName] = data;
@@ -41,7 +38,7 @@ describe('transformer util', () => {
 
   // TODO: add tests for all kinds of comments!
   // -> verify the hacks I added in transformer_utils!
-  it.only('should synthesize comments', () => {
+  it('should synthesize comments', () => {
     function transformComments(context: ts.TransformationContext) {
       return (sourceFile: ts.SourceFile): ts.SourceFile => {
         return visitNode(sourceFile);