Add a proper test.

And fix loads of bugs.

crates/cli-support/src/js/mod.rs

@@ -377,7 +377,7 @@ impl<'a> Context<'a> {
                         }
                         if (type == 'function') {
                             const name = val.name;
-                            if (typeof name == 'string') {
+                            if (typeof name == 'string' && name.length > 0) {
                                 return `Function(${name})`;
                             } else {
                                 return 'Function';
@@ -391,16 +391,16 @@ impl<'a> Context<'a> {
                                 debug += debug_str(val[0]);
                             }
                             for(let i = 1; i < length; i++) {
-                                debug += debug_str(val[i]) + ', ';
+                                debug += ', ' + debug_str(val[i]);
                             }
                             debug += ']';
                             return debug;
                         }
                         // Test for built-in
-                        const builtInMatches = /\\[object ([^])+\\]/.exec(toString.call(val));
+                        const builtInMatches = /\\[object ([^\\]]+)\\]/.exec(toString.call(val));
                         let className;
-                        if (builtInMatches.len > 0) {
+                        if (builtInMatches.length > 1) {
-                            className = builtInMatches[0];
+                            className = builtInMatches[1];
                         } else {
                             // Failed to match the standard '[object ClassName]'
                             return toString.call(val);
@@ -414,6 +414,7 @@ impl<'a> Context<'a> {
                             } catch (_) {
                                 return 'Object';
                             }
+                        // TODO we could test for more things here, like `Set`s and `Map`s.
                         } else {
                             return className;
                         }

tests/wasm/api.js

@@ -41,3 +41,17 @@ exports.js_eq_works = () => {
     assert.strictEqual(wasm.eq_test(x, x), true);
     assert.strictEqual(wasm.eq_test1(x), true);
 };
+
+exports.debug_values = () => ([
+    null,
+    undefined,
+    0,
+    1.0,
+    true,
+    [1,2,3],
+    "string",
+    {test: "object"},
+    [1.0, [2.0, 3.0]],
+    () => (null),
+    new Set(),
+]);

tests/wasm/api.rs

@@ -8,6 +8,7 @@ extern "C" {
     fn js_works();
     fn js_eq_works();
     fn assert_null(v: JsValue);
+    fn debug_values() -> JsValue;
 }
 
 #[wasm_bindgen_test]
@@ -145,3 +146,24 @@ fn memory_accessor_appears_to_work() {
         .for_each(&mut |val, _, _| v.push(val));
     assert_eq!(v, [3, 0, 0, 0]);
 }
+
+#[wasm_bindgen_test]
+fn debug_output() {
+    let test_iter = debug_values().dyn_into::<js_sys::Array>().unwrap().values().into_iter();
+    let expecteds = vec![
+        "JsValue(null)",
+        "JsValue(undefined)",
+        "JsValue(0)",
+        "JsValue(1)",
+        "JsValue(true)",
+        "JsValue([1, 2, 3])",
+        "JsValue(\"string\")",
+        "JsValue(Object({\"test\":\"object\"}))",
+        "JsValue([1, [2, 3]])",
+        "JsValue(Function)",
+        "JsValue(Set)",
+    ];
+    for (test, expected) in test_iter.zip(expecteds) {
+        assert_eq!(format!("{:?}", test.unwrap()), expected);
+    }
+}