remove subtle diffs

Author: uhyo

build/diff.ts

@@ -23,7 +23,10 @@ async function main() {
   const libFiles = await getLibFiles();
   const hasDiffFiles: string[] = [];
   for (const [targetFile, sourceFile] of libFiles.entries()) {
-    const betterLib = generate(tsLibDir, targetFile, sourceFile, false);
+    const betterLib = generate(tsLibDir, targetFile, sourceFile, {
+      emitOriginalAsComment: false,
+      emitNoDefaultLib: false,
+    });
     if (betterLib === undefined) {
       continue;
     }

build/lib.ts

@@ -21,7 +21,10 @@ async function main() {
 
   // modify each lib file
   for (const [targetFile, sourceFile] of libFiles.entries()) {
-    let result = generate(tsLibDir, targetFile, sourceFile, true);
+    let result = generate(tsLibDir, targetFile, sourceFile, {
+      emitOriginalAsComment: true,
+      emitNoDefaultLib: true,
+    });
     if (result === undefined) {
       continue;
     }

build/logic/generate.ts

@@ -6,14 +6,19 @@ import { projectDir } from "./projectDir";
 
 const betterLibDir = path.join(projectDir, "lib");
 
+type GenerateOptions = {
+  emitOriginalAsComment?: boolean;
+  emitNoDefaultLib?: boolean;
+};
+
 /**
  * Generate one better lib file.
  */
 export function generate(
   tsLibDir: string,
   targetFile: string,
   sourceFile: string,
-  emitOriginalAsComment: boolean
+  { emitOriginalAsComment = false, emitNoDefaultLib = false }: GenerateOptions
 ): string | undefined {
   const tsLibFile = path.join(tsLibDir, sourceFile);
   const originalProgram = ts.createProgram([tsLibFile], {});
@@ -24,9 +29,11 @@ export function generate(
 
   const printer = ts.createPrinter();
 
-  // This is used as a good indicator of being a default lib file
-  let result = `/// <reference no-default-lib="true"/>
-`;
+  let result = emitNoDefaultLib
+    ? // This is used as a good indicator of being a default lib file
+      `/// <reference no-default-lib="true"/>
+`
+    : "";
 
   const replacementTargets = scanBetterFile(printer, targetFile);