Speed up sanitizeLibFileText

Author: jakebailey

src/harness/harnessIO.ts

@@ -233,24 +233,27 @@ export namespace Compiler {
     export const es2015DefaultLibFileName = "lib.es2015.d.ts";
 
     // Cache of lib files from "built/local"
-    export let libFileNameSourceFileMap: Map<string, ts.SourceFile> | undefined;
+    export let libFileNameSourceFileMap: Map<string, { file: ts.SourceFile; stringified: string; }> | undefined;
 
     export function getDefaultLibrarySourceFile(fileName: string = defaultLibFileName): ts.SourceFile | undefined {
         if (!isDefaultLibraryFile(fileName)) {
             return undefined;
         }
 
         if (!libFileNameSourceFileMap) {
+            const file = createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts")!, /*languageVersion*/ ts.ScriptTarget.Latest);
             libFileNameSourceFileMap = new Map(Object.entries({
-                [defaultLibFileName]: createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts")!, /*languageVersion*/ ts.ScriptTarget.Latest),
+                [defaultLibFileName]: { file, stringified: JSON.stringify(file.text) },
             }));
         }
 
         let sourceFile = libFileNameSourceFileMap.get(fileName);
         if (!sourceFile) {
-            libFileNameSourceFileMap.set(fileName, sourceFile = createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName)!, ts.ScriptTarget.Latest));
+            const file = createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName)!, ts.ScriptTarget.Latest)
+            sourceFile = { file, stringified: JSON.stringify(file.text) };
+            libFileNameSourceFileMap.set(fileName, sourceFile);
         }
-        return sourceFile;
+        return sourceFile.file;
     }
 
     export function getDefaultLibFileName(options: ts.CompilerOptions): string {

src/harness/tsserverLogger.ts

@@ -144,8 +144,8 @@ function sanitizeHarnessLSException(s: string) {
 
 export function sanitizeLibFileText(s: string): string {
     Compiler.libFileNameSourceFileMap?.forEach((lib, fileName) => {
-        s = replaceAll(s, JSON.stringify(lib.text), `${fileName}-Text`);
-        s = replaceAll(s, lib.text, `${fileName}-Text`);
+        s = replaceAll(s, lib.stringified, `${fileName}-Text`);
+        s = replaceAll(s, lib.file.text, `${fileName}-Text`);
     });
     return s;
 }