Make new harness fake host more performant in large complications

src/compiler/core.ts

@@ -2223,6 +2223,7 @@ namespace ts {
         const reduced = [components[0]];
         for (let i = 1; i < components.length; i++) {
             const component = components[i];
+            if (!component) continue;
             if (component === ".") continue;
             if (component === "..") {
                 if (reduced.length > 1) {

src/compiler/moduleNameResolver.ts

@@ -119,7 +119,12 @@ namespace ts {
     export function readJson(path: string, host: { readFile(fileName: string): string | undefined }): object {
         try {
             const jsonText = host.readFile(path);
-            return jsonText ? JSON.parse(jsonText) : {};
+            if (!jsonText) return {};
+            const result = parseConfigFileTextToJson(path, jsonText);
+            if (result.error) {
+                return {};
+            }
+            return result.config;
         }
         catch (e) {
             // gracefully handle if readFile fails or returns not JSON

src/harness/fakes.ts

@@ -39,9 +39,7 @@ namespace fakes {
         public readFile(path: string) {
             try {
                 const content = this.vfs.readFileSync(path, "utf8");
-                return content === undefined ? undefined :
-                    vpath.extname(path) === ".json" ? utils.removeComments(utils.removeByteOrderMark(content), utils.CommentRemoval.leadingAndTrailing) :
-                        utils.removeByteOrderMark(content);
+                return content === undefined ? undefined : utils.removeByteOrderMark(content);
             }
             catch {
                 return undefined;
@@ -203,6 +201,7 @@ namespace fakes {
         public readonly sys: System;
         public readonly defaultLibLocation: string;
         public readonly outputs: documents.TextDocument[] = [];
+        private readonly _outputsMap: collections.SortedMap<string, number>;
         public readonly traces: string[] = [];
         public readonly shouldAssertInvariants = !Harness.lightMode;
 
@@ -218,6 +217,7 @@ namespace fakes {
             this._newLine = ts.getNewLineCharacter(options, () => this.sys.newLine);
             this._sourceFiles = new collections.SortedMap<string, ts.SourceFile>({ comparer: sys.vfs.stringComparer, sort: "insertion" });
             this._setParentNodes = setParentNodes;
+            this._outputsMap = new collections.SortedMap(this.vfs.stringComparer);
         }
 
         public get vfs() {
@@ -267,13 +267,11 @@ namespace fakes {
             const document = new documents.TextDocument(fileName, content);
             document.meta.set("fileName", fileName);
             this.vfs.filemeta(fileName).set("document", document);
-            const index = this.outputs.findIndex(output => this.vfs.stringComparer(document.file, output.file) === 0);
-            if (index < 0) {
+            if (!this._outputsMap.has(document.file)) {
+                this._outputsMap.set(document.file, this.outputs.length);
                 this.outputs.push(document);
             }
-            else {
-                this.outputs[index] = document;
-            }
+            this.outputs[this._outputsMap.get(document.file)] = document;
         }
 
         public trace(s: string): void {

src/harness/utils.ts

@@ -2,31 +2,6 @@
  * Common utilities
  */
 namespace utils {
-    const leadingCommentRegExp = /^(\s*\/\*[^]*?\*\/\s*|\s*\/\/[^\r\n\u2028\u2029]*[\r\n\u2028\u2029]*)+/;
-    const trailingCommentRegExp = /(\s*\/\*[^]*?\*\/\s*|\s*\/\/[^\r\n\u2028\u2029]*[\r\n\u2028\u2029]*)+$/;
-    const leadingAndTrailingCommentRegExp = /^(\s*\/\*[^]*?\*\/\s*|\s*\/\/[^\r\n\u2028\u2029]*[\r\n\u2028\u2029]*)+|(\s*\/\*[^]*?\*\/\s*|\s*\/\/[^\r\n\u2028\u2029]*[\r\n\u2028\u2029]*)+$/g;
-    const allCommentRegExp = /(['"])(?:(?!\1).|\\[^])*\1|(\/\*[^]*?\*\/|\/\/[^\r\n\u2028\u2029]*[\r\n\u2028\u2029]*)/g;
-
-    export const enum CommentRemoval {
-        leading,
-        trailing,
-        leadingAndTrailing,
-        all
-    }
-
-    export function removeComments(text: string, removal: CommentRemoval) {
-        switch (removal) {
-            case CommentRemoval.leading:
-                return text.replace(leadingCommentRegExp, "");
-            case CommentRemoval.trailing:
-                return text.replace(trailingCommentRegExp, "");
-            case CommentRemoval.leadingAndTrailing:
-                return text.replace(leadingAndTrailingCommentRegExp, "");
-            case CommentRemoval.all:
-                return text.replace(allCommentRegExp, (match, quote) => quote ? match : "");
-        }
-    }
-
     const testPathPrefixRegExp = /(?:(file:\/{3})|\/)\.(ts|lib|src)\//g;
     export function removeTestPathPrefixes(text: string, retainTrailingDirectorySeparator?: boolean) {
         return text !== undefined ? text.replace(testPathPrefixRegExp, (_, scheme) => scheme || (retainTrailingDirectorySeparator ? "/" : "")) : undefined;