Add `tsconfig.json` to `bun-types` (#2587)

* Add tsconfig.json to bun-types. Document 'extends' pattern.

* Updates

* Update bun init to use extends:bun-types

* Update type:module recommendation

* Add note about transpilation. Closes #2553

* Make typescript a peer dep

* Revert changes to docs

* Revert tsconfig extends

* Update readme

* FMC

* Undo changed

4 files changed, 63 insertions, 20 deletions

diff --git a/packages/bun-types/README.md b/packages/bun-types/README.md
index fc4128388..19964c6f8 100644
--- a/packages/bun-types/README.md
+++ b/packages/bun-types/README.md
@@ -1,4 +1,4 @@
-# Bun TypeScript type definitions
+# TypeScript types for Bun
 
 <p align="center">
   <a href="https://bun.sh"><img src="https://bun.sh/logo@2x.png" alt="Logo"></a>
@@ -21,31 +21,25 @@ Add this to your `tsconfig.json` or `jsconfig.json`:
 
 ```jsonc-diff
   {
-    "compilerOptions": {
-      // ...
-+     "types": ["bun-types"]
-    }
+    
++   "types": ["bun-types"],
+    
+    // other options...
   }
 ```
 
 # Contributing
 
-`bun-types` is generated via [./bundle.ts](./scripts/bundle.ts).
+`bun-types` is generated via [./scripts/bundle.ts](./scripts/bundle.ts).
 
-## Adding a new file
+To add a new file, add it under `packages/bun-types`. Then add a [triple-slash directive](https://www.typescriptlang.org/docs/handbook/triple-slash-directives.html) pointing to it inside [./index.d.ts](./index.d.ts).
 
-1. Add it to [./index.d.ts](./index.d.ts)
-
-## How to generate types.d.ts
-
-[`./bundle.ts`](./bundle.ts) merges the types in this folder into a single file.
+```diff
++ /// <reference path="./newfile.d.ts" />
+```
 
-To run it:
+[`./bundle.ts`](./bundle.ts) merges the types in this folder into a single file. To run it:
 
 ```bash
 bun build
 ```
-
-# Generated docs
-
-**[📚 See here for docs](https://oven-sh.github.io/bun-types/)**
diff --git a/packages/bun-types/scripts/bundle.ts b/packages/bun-types/scripts/bundle.ts
index 1f9403513..aa91a3dfa 100644
--- a/packages/bun-types/scripts/bundle.ts
+++ b/packages/bun-types/scripts/bundle.ts
@@ -50,7 +50,7 @@ const packageJSON = {
   description:
     "Type definitions for Bun, an incredibly fast JavaScript runtime",
   types: "types.d.ts",
-  files: ["types.d.ts", "README.md"],
+  files: ["types.d.ts", "README.md", "tsconfig.json"],
   private: false,
   keywords: ["bun", "bun.js", "types"],
   repository: "https://github.com/oven-sh/bun",
@@ -62,6 +62,31 @@ await write(
   JSON.stringify(packageJSON, null, 2) + "\n",
 );
 
+const tsConfig = {
+  compilerOptions: {
+    lib: ["ESNext"],
+    target: "ESNext",
+    module: "ESNext",
+    moduleResolution: "bundler",
+    moduleDetection: "force",
+    resolveJsonModule: true,
+    strict: true,
+    downlevelIteration: true,
+    skipLibCheck: true,
+    jsx: "react-jsx",
+    allowImportingTsExtensions: true,
+    allowSyntheticDefaultImports: true,
+    forceConsistentCasingInFileNames: true,
+    allowJs: true,
+    types: ["bun-types"],
+  },
+};
+
+await write(
+  resolve(folder, "tsconfig.json"),
+  JSON.stringify(tsConfig, null, 2) + "\n",
+);
+
 await write(
   resolve(folder, "README.md"),
   file(resolve(import.meta.dir, "..", "README.md")),
diff --git a/src/cli/init_command.zig b/src/cli/init_command.zig
index a7abd02e8..1b95d47fa 100644
--- a/src/cli/init_command.zig
+++ b/src/cli/init_command.zig
@@ -282,6 +282,22 @@ pub const InitCommand = struct {
                 break :brk true;
             };
 
+            const needs_typescript_dependency = brk: {
+                if (fields.object.get("devDependencies")) |deps| {
+                    if (deps.hasAnyPropertyNamed(&.{"typescript"})) {
+                        break :brk false;
+                    }
+                }
+
+                if (fields.object.get("peerDependencies")) |deps| {
+                    if (deps.hasAnyPropertyNamed(&.{"typescript"})) {
+                        break :brk false;
+                    }
+                }
+
+                break :brk true;
+            };
+
             if (needs_dev_dependencies) {
                 var dev_dependencies = fields.object.get("devDependencies") orelse js_ast.Expr.init(js_ast.E.Object, js_ast.E.Object{}, logger.Loc.Empty);
                 const version = comptime brk: {
@@ -293,6 +309,12 @@ pub const InitCommand = struct {
                 try dev_dependencies.data.e_object.putString(alloc, "bun-types", comptime std.fmt.comptimePrint("^{any}", .{version.fmt("")}));
                 try fields.object.put(alloc, "devDependencies", dev_dependencies);
             }
+
+            if (needs_typescript_dependency) {
+                var peer_dependencies = fields.object.get("peer_dependencies") orelse js_ast.Expr.init(js_ast.E.Object, js_ast.E.Object{}, logger.Loc.Empty);
+                try peer_dependencies.data.e_object.putString(alloc, "typescript", "^5.0.0");
+                try fields.object.put(alloc, "peerDependencies", peer_dependencies);
+            }
         }
 
         write_package_json: {
diff --git a/src/cli/tsconfig-for-init.json b/src/cli/tsconfig-for-init.json
index 5c0ced989..b8cfbf636 100644
--- a/src/cli/tsconfig-for-init.json
+++ b/src/cli/tsconfig-for-init.json
@@ -6,10 +6,12 @@
     "module": "esnext",
     "target": "esnext",
     "moduleResolution": "bundler",
+    "moduleDetection": "force",
+    "allowImportingTsExtensions": true,
     "strict": true,
     "downlevelIteration": true,
     "skipLibCheck": true,
-    "jsx": "react-jsx",
+    "jsx": "preserve",
     "allowSyntheticDefaultImports": true,
     "forceConsistentCasingInFileNames": true,
     "allowJs": true,
@@ -17,4 +19,4 @@
       "bun-types" // add Bun global
     ]
   }
-}
\ No newline at end of file
+}