Inline & simplify the node 8 extend workaround in evaluateSnippets.

lib/evaluateSnippets.js

@@ -26,16 +26,6 @@ try {
   };
 }
 
-function extend(target) {
-  for (var i = 1; i < arguments.length; i += 1) {
-    var source = arguments[i];
-    for (const key of Object.keys(source)) {
-      target[key] = source[key];
-    }
-  }
-  return target;
-}
-
 function isPromise(value) {
   return (
     value &&
@@ -65,7 +55,7 @@ function getErrorMessage(expect, format, error) {
 }
 
 module.exports = async function(snippets, options) {
-  var oldGlobal = extend({}, global);
+  var oldGlobal = Object.assign({}, global);
   var expect = createExpect(options);
   global.expect = expect.clone();
   global.require = require;
@@ -149,6 +139,8 @@ module.exports = async function(snippets, options) {
     }
   }
 
-  // local function used for compatibility with node 8
-  extend(global, oldGlobal);
+  // inline function used for compatibility with node 8
+  for (const key of Object.keys(oldGlobal)) {
+    global[key] = oldGlobal[key];
+  }
 };