add server to monorepo.

packages/server/src/api/middleware/JSONResponseTransformer.ts

@@ -0,0 +1,37 @@
+import { snakeCase } from 'lodash';
+import { mapKeysDeep } from 'utils';
+
+/**
+ * Express middleware for intercepting and transforming json responses
+ *
+ * @param {function} [condition] - takes the req and res and returns a boolean indicating whether to run the transform on this response
+ * @param {function} transform - takes an object passed to res.json and returns a replacement object
+ * @return {function} the middleware
+ */
+export function JSONResponseTransformer(transform: Function) {
+  const replaceJson = (res) => {
+    var origJson = res.json;
+  
+    res.json = function (val) {
+      const json = JSON.parse(JSON.stringify(val));
+
+      return origJson.call(res, transform(json));
+    };
+  };
+
+  return function (req, res, next) {
+    replaceJson(res);
+    next();
+  };
+}
+
+/**
+ * Transformes the given response keys to snake case.
+ * @param response
+ * @returns
+ */
+export const snakecaseResponseTransformer = (response) => {
+  return mapKeysDeep(response, (value, key) => {
+    return snakeCase(key);
+  });
+};