Index: node_modules/err-code/index.js
===================================================================
--- node_modules/err-code/index.js	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
+++ node_modules/err-code/index.js	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
@@ -0,0 +1,47 @@
+'use strict';
+
+function assign(obj, props) {
+    for (const key in props) {
+        Object.defineProperty(obj, key, {
+            value: props[key],
+            enumerable: true,
+            configurable: true,
+        });
+    }
+
+    return obj;
+}
+
+function createError(err, code, props) {
+    if (!err || typeof err === 'string') {
+        throw new TypeError('Please pass an Error to err-code');
+    }
+
+    if (!props) {
+        props = {};
+    }
+
+    if (typeof code === 'object') {
+        props = code;
+        code = undefined;
+    }
+
+    if (code != null) {
+        props.code = code;
+    }
+
+    try {
+        return assign(err, props);
+    } catch (_) {
+        props.message = err.message;
+        props.stack = err.stack;
+
+        const ErrClass = function () {};
+
+        ErrClass.prototype = Object.create(Object.getPrototypeOf(err));
+
+        return assign(new ErrClass(), props);
+    }
+}
+
+module.exports = createError;