hasOwn & catchError utils (for extensions)

src/extension-support/usb-unsandboxed-object.js

@@ -1,9 +1,32 @@
 const ContextMenuContext = require('./context-menu-context');
 const Util = require('../util/usb-util');
+const hasOwn = (obj, prop) => Object.prototype.hasOwnProperty.call(obj, prop):
+const catchError = async (promise, errors) => {
+    if (!(promise instanceof Promise)) {
+        throw new TypeError('Expected "promise" to be PromiseLike.');
+    }
+    if (errors !== undefined) {
+        if (!Array.isArray(errors)) {
+            throw new TypeError('Expected "errors" to be undefined or an array.');
+        }
+        if (!errors[0]) {
+            throw new RangeError('Expected "errors" array to be bigger than 0.');
+        }
+    }
+    return promise.then(v => [undefined, v]).catch(e => {
+        if (
+            errors !== undefined ||
+            !errors.some(p => (e instanceof p))
+        ) return;
+        return [e, undefined];
+    });
+};
 
 module.exports = function() {
-  return {
-    ContextMenuContext,
-    Util
-  };
+    return {
+        ContextMenuContext,
+        Util,
+        hasOwn,
+        catchError
+    };
 };