Example (#4730)

* add tests for example feature
* refactor ParameterRow value setter logic
* aside: fix property access in sampleFromSchema
* prioritize media type examples for OAS3 responses
* use `example` in schema level example
* refactor: move stringify to utils
* prioritize media type examples in OAS3 request bodies
* modify nightwatch config
* fix parameter/response regressions
* reorder and broaden default value sources
* update lockfile

src/core/utils.js

@@ -760,3 +760,24 @@ export function deeplyStripKey(input, keyToStrip, predicate = () => true) {
 
   return obj
 }
+
+export function stringify(thing) {
+  if (typeof thing === "string") {
+    return thing
+  }
+
+  if (thing.toJS) {
+    thing = thing.toJS()
+  }
+
+  if (typeof thing === "object" && thing !== null) {
+    try {
+      return JSON.stringify(thing, null, 2)
+    }
+    catch (e) {
+      return String(thing)
+    }
+  }
+
+  return thing.toString()
+}