feat: option to show common query parameters (#4245)

* extend getExtensions

Add optional param to getExtensions that can retrieve more stuff

* Add getCommonExtensions

* Trim trailing spaces

* Remove unused parameter

* Move the format inline with the param type

* correction to UnitTest

test/core/utils.js

@@ -1,6 +1,6 @@
 /* eslint-env mocha */
 import expect from "expect"
-import { fromJS, OrderedMap } from "immutable"
+import { Map, fromJS, OrderedMap } from "immutable"
 import {
   mapToList,
   parseSearch,
@@ -20,6 +20,8 @@ import {
   getAcceptControllingResponse,
   createDeepLinkPath,
   escapeDeepLinkPath,
+  getExtensions,
+  getCommonExtensions,
   sanitizeUrl,
   extractFileNameFromContentDispositionHeader,
   deeplyStripKey
@@ -943,6 +945,24 @@ describe("utils", function() {
     })
   })
 
+  describe("getExtensions", function() {
+    const objTest = Map([[ "x-test", "a"], ["minimum", "b"]])
+    it("does not error on empty array", function() {
+      const result1 = getExtensions([])
+      expect(result1).toEqual([])
+      const result2 = getCommonExtensions([])
+      expect(result2).toEqual([])
+    })
+    it("gets only the x- keys", function() {
+      const result = getExtensions(objTest)
+      expect(result).toEqual(Map([[ "x-test", "a"]]))
+    })
+    it("gets the common keys", function() {
+      const result = getCommonExtensions(objTest, true)
+      expect(result).toEqual(Map([[ "minimum", "b"]]))
+    })
+  })
+  
   describe("deeplyStripKey", function() {
     it("should filter out a specified key", function() {
       const input = {