pre-request script working

functions/preRequest.js

@@ -0,0 +1,17 @@
+export default function getEnvironmentVariablesFromScript(script) {
+  let _variables = {};
+
+  // the pw object is the proxy by which pre-request scripts can pass variables to the request.
+  // for security and control purposes, this is the only way a pre-request script should modify variables.
+  let pw = {
+    environment: {
+      set: (key, value) => _variables[key] = value,
+    },
+    // globals that the script is allowed to have access to.
+  };
+
+  // run pre-request script within this function so that it has access to the pw object.
+  (new Function('pw', script))(pw);
+
+  return _variables;
+}