diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 53e5059a..b7a0b55f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -15,12 +15,22 @@ The repository is organized as follows:
 │   ├── browser_app_entry.tsx   # Entry point for browser app, hosted on GitHub pages.
 │   └── vscode_entry.tsx        # Entry point for VS Code app, output placed under `vscode/assets`.
 ├── vscode/             # The VS Code extension.
-└── rustlib/            # Rust library exporting Wasm functions.
-    └── pkg/            # Output directory for rustlib, installed from package.json via `"./rustlib/pkg"`.
+├── rustlib/            # Rust library exporting Wasm functions.
+│   └── pkg/            # Output directory for rustlib, installed from package.json via `"./rustlib/pkg"`.
+└── tslib/              # TypeScript library shared for common use.
+    ├── react/                  # Common React components.
+    ├── storage/                # Common code for handling storage.
+    └── types/                  # Common TypeScript types.
 ```
 
 ## Python package
 
+#### Building TypeScript packages
+
+```
+$ make tslib
+```
+
 #### Compiling TypeScript files
 
 Node.js v16 is required to compile TypeScript files.
diff --git a/optuna_dashboard/package-lock.json b/optuna_dashboard/package-lock.json
index d888df64..df49f5e1 100644
--- a/optuna_dashboard/package-lock.json
+++ b/optuna_dashboard/package-lock.json
@@ -60,7 +60,10 @@
       "name": "@optuna/types",
       "version": "0.0.1",
       "dev": true,
-      "license": "MIT"
+      "license": "MIT",
+      "devDependencies": {
+        "typescript": "^5.4.5"
+      }
     },
     "node_modules/@ampproject/remapping": {
       "version": "2.3.0",