diff --git a/cli/build.rs b/cli/build.rs
index 983c5f95..deba4381 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -17,20 +17,13 @@ fn main() {
     );
 }
 
-fn required_files() -> Vec<&'static Path> {
-    return vec![
-        Path::new("../lib/binding_web/tree-sitter.js"),
-        Path::new("../lib/binding_web/tree-sitter.wasm")
-        ];
-}
-
 fn wasm_files_present() -> bool {
-    for path in required_files() {
-        if !path.exists() {
-            return false
-        }
-    }
-    return true
+    let paths = [
+        "../lib/binding_web/tree-sitter.js",
+        "../lib/binding_web/tree-sitter.wasm",
+    ];
+
+    return paths.iter().all(|p| Path::new(p).exists())
 }
 
 fn read_git_sha() -> Option<String> {
diff --git a/docs/section-6-contributing.md b/docs/section-6-contributing.md
index 690f38f6..4ccaddea 100644
--- a/docs/section-6-contributing.md
+++ b/docs/section-6-contributing.md
@@ -29,7 +29,7 @@ git clone https://github.com/tree-sitter/tree-sitter
 cd tree-sitter
 ```
 
-To use the `web-ui` command, you'll need to build the WASM library. If you have emscripten installed, this will use your `emcc` compiler. Otherwise, it will use Docker:
+Optionally, build the WASM library. If you skip this step, then the `tree-sitter web-ui` command will require an internet connection. If you have emscripten installed, this will use your `emcc` compiler. Otherwise, it will use Docker:
 
 ```sh
 ./script/build-wasm