Use "lib" in tsconfigs instead of "target". (#13968)

* Use "lib" in tsconfigs instead of "target".

Only add "dom" to libraries that need it. This is determined by a script, so many libraries that have "dom" maybe should not.

* Update new-package and readme

* Add back "target" where necessary

scripts/generate-tsconfigs.ts

@@ -1,4 +1,4 @@
-// Usage: ts-node generate-tsconfigs
+// Usage: ts-node generate-tsconfigs.ts
 
 /// <reference types="node" />
 
@@ -11,17 +11,31 @@ function repeat(s: string, count: number) {
 
 const home = path.join(__dirname, '..');
 
-const dirs = fs.readdirSync(home).filter(d => !(d.startsWith(".") || d === "node_modules" || d === "scripts"));
-for (const dir of dirs.map(d => path.join(home, d))) {
+for (const dirName of fs.readdirSync(home)) {
+	if (dirName.startsWith(".") || dirName === "node_modules" || dirName === "scripts") {
+		continue;
+	}
+
+	const dir = path.join(home, dirName);
 	const stats = fs.lstatSync(dir);
 	if (stats.isDirectory()) {
-		const target = path.join(dir, 'tsconfig.json');
-		let json = JSON.parse(fs.readFileSync(target, 'utf-8'));
-		json = fix(json);
-		fs.writeFileSync(target, JSON.stringify(json, undefined, 4), "utf-8");
+		fixTsconfig(dir);
+		// Also do it for old versions
+		for (const subdir of fs.readdirSync(dir)) {
+			if (/^v\d+$/.test(subdir)) {
+				fixTsconfig(path.join(dir, subdir));
+			}
+		}
 	}
 }
 
+function fixTsconfig(dir: string): void {
+	const target = path.join(dir, 'tsconfig.json');
+	let json = JSON.parse(fs.readFileSync(target, 'utf-8'));
+	json = fix(json);
+	fs.writeFileSync(target, JSON.stringify(json, undefined, 4), "utf-8");
+}
+
 function fix(config: any): any {
 	const out: any = {};
 	for (const key in config) {
@@ -38,9 +52,7 @@ function fixCompilerOptions(config: any): any {
 	const out: any = {};
 	for (const key in config) {
 		out[key] = config[key];
-		if (key === "noImplicitAny") {
-			out.noImplicitThis = true;
-		}
+		// Do something interesting here
 	}
 	return out;
 }

scripts/new-package.ts

@@ -79,7 +79,7 @@ function getTSConfig() {
     return {
         "compilerOptions": {
             "module": "commonjs",
-            "target": "es6",
+            "lib": ["es6"],
             "noImplicitAny": true,
             "noImplicitThis": true,
             "strictNullChecks": true,