More useful result pretty printing for d8

src/d8.js

Index: src/d8.js
diff --git a/src/d8.js b/src/d8.js
index 6a4ecb73304726203d037ddf38891a6bdb7a2fa1..1ff0ce8980dda2ed8843364eac299931a9a3dfec 100644
--- a/src/d8.js
+++ b/src/d8.js
@@ -2194,3 +2194,59 @@ function SimpleArrayToJSON_(array) {
   json += ']';
   return json;
 }
+
+
+// A more universal stringify that supports more types than JSON.
+// Used by the d8 shell to output results.
+var stringifyDepthLimit = 4;  // To avoid crashing on cyclic objects
+
+function Stringify(x, depth) {
+  if (depth === undefined)
+    depth = stringifyDepthLimit;
+  else if (depth === 0)
+    return "*";
+  switch (typeof x) {
+    case "undefined":
+      return "undefined";
+    case "boolean":
+    case "number":
+    case "function":
+      return x.toString();
+    case "string":
+      return "\"" + x.toString() + "\"";
+    // TODO(rossberg): add symbol case
+    case "object":
+      if (x === null) return "null";
+      if (x.constructor && x.constructor.name === "Array") {
+        var elems = [];
+        for (var i = 0; i < x.length; ++i) {
+          elems.push(
+            {}.hasOwnProperty.call(x, i) ? Stringify(x[i], depth - 1) : "");
+        }
+        return "[" + elems.join(", ") + "]";
+      }
+      try {
+        var string = String(x);
+        if (string && string !== "[object Object]") return string;
+      } catch(e) {}
+      var props = [];
+      for (var name in x) {
+        var desc = Object.getOwnPropertyDescriptor(x, name);
+        if (desc === void 0) continue;
+        if ("value" in desc) {
+          props.push(name + ": " + Stringify(desc.value, depth - 1));
+        }
+        if ("get" in desc) {
+          var getter = desc.get.toString();
+          props.push("get " + name + getter.slice(getter.indexOf('(')));
+        }
+        if ("set" in desc) {
+          var setter = desc.set.toString();
+          props.push("set " + name + setter.slice(setter.indexOf('(')));
+        }
+      }
+      return "{" + props.join(", ") + "}";
+    default:
+      return "[crazy non-standard shit]";
+  }
+}