Refactor `parseUrlPathname` and delete unused `parseUrl`

I deleted `parseUrl` utility because it was only used within
`parseUrlPathname`. I then refactor `parseUrlPathname` using the `URL`
inferface[1].

[1] https://developer.mozilla.org/en-US/docs/Web/API/URL

app/assets/javascripts/lib/utils/common_utils.js

@@ -130,19 +130,6 @@ export const isInViewport = (el, offset = {}) => {
   );
 };
 
-export const parseUrl = (url) => {
-  const parser = document.createElement('a');
-  parser.href = url;
-  return parser;
-};
-
-export const parseUrlPathname = (url) => {
-  const parsedUrl = parseUrl(url);
-  // parsedUrl.pathname will return an absolute path for Firefox and a relative path for IE11
-  // We have to make sure we always have an absolute path.
-  return parsedUrl.pathname.charAt(0) === '/' ? parsedUrl.pathname : `/${parsedUrl.pathname}`;
-};
-
 export const isMetaKey = (e) => e.metaKey || e.ctrlKey || e.altKey || e.shiftKey;
 
 // Identify following special clicks

app/assets/javascripts/lib/utils/url_utility.js

@@ -18,6 +18,20 @@ function resetRegExp(regex) {
   return regex;
 }
 
+/**
+ * Returns the absolute pathname for a relative or absolute URL string.
+ *
+ * A few examples of inputs and outputs:
+ * 1) 'http://a.com/b/c/d' => '/b/c/d'
+ * 2) '/b/c/d' => '/b/c/d'
+ * 3) 'b/c/d' => '/b/c/d' or '[path]/b/c/d' depending of the current path of the
+ *    document.location
+ */
+export const parseUrlPathname = (url) => {
+  const { pathname } = new URL(url, document.location.href);
+  return pathname;
+};
+
 // Returns a decoded url parameter value
 // - Treats '+' as '%20'
 function decodeUrlParameter(val) {

app/assets/javascripts/merge_request_tabs.js

@@ -2,13 +2,8 @@
 import { GlBreakpointInstance as bp } from '@gitlab/ui/dist/utils';
 import $ from 'jquery';
 import Vue from 'vue';
-import {
-  getCookie,
-  parseUrlPathname,
-  isMetaClick,
-  parseBoolean,
-  scrollToElement,
-} from '~/lib/utils/common_utils';
+import { getCookie, isMetaClick, parseBoolean, scrollToElement } from '~/lib/utils/common_utils';
+import { parseUrlPathname } from '~/lib/utils/url_utility';
 import createEventHub from '~/helpers/event_hub_factory';
 import BlobForkSuggestion from './blob/blob_fork_suggestion';
 import Diff from './diff';

spec/frontend/lib/utils/common_utils_spec.js

@@ -51,31 +51,6 @@ describe('common_utils', () => {
     });
   });
 
-  describe('parseUrl', () => {
-    it('returns an anchor tag with url', () => {
-      expect(commonUtils.parseUrl('/some/absolute/url').pathname).toContain('some/absolute/url');
-    });
-
-    it('url is escaped', () => {
-      // IE11 will return a relative pathname while other browsers will return a full pathname.
-      // parseUrl uses an anchor element for parsing an url. With relative urls, the anchor
-      // element will create an absolute url relative to the current execution context.
-      // The JavaScript test suite is executed at '/' which will lead to an absolute url
-      // starting with '/'.
-      expect(commonUtils.parseUrl('" test="asf"').pathname).toContain('/%22%20test=%22asf%22');
-    });
-  });
-
-  describe('parseUrlPathname', () => {
-    it('returns an absolute url when given an absolute url', () => {
-      expect(commonUtils.parseUrlPathname('/some/absolute/url')).toEqual('/some/absolute/url');
-    });
-
-    it('returns an absolute url when given a relative url', () => {
-      expect(commonUtils.parseUrlPathname('some/relative/url')).toEqual('/some/relative/url');
-    });
-  });
-
   describe('handleLocationHash', () => {
     beforeEach(() => {
       jest.spyOn(window.document, 'getElementById');

spec/frontend/lib/utils/url_utility_spec.js

@@ -22,6 +22,27 @@ beforeEach(() => {
 });
 
 describe('URL utility', () => {
+  describe('parseUrlPathname', () => {
+    it('returns an absolute url when given an absolute url', () => {
+      expect(urlUtils.parseUrlPathname('/some/absolute/url')).toBe('/some/absolute/url');
+    });
+
+    it('returns an absolute url when given a relative url', () => {
+      expect(urlUtils.parseUrlPathname('some/relative/url')).toBe('/some/relative/url');
+    });
+
+    it('returns an absolute url that includes the document.location path when given a relative url', () => {
+      // Change the location to see the `/mypath/` included in the result
+      setWindowLocation(`${TEST_HOST}/mypath/`);
+
+      expect(urlUtils.parseUrlPathname('some/relative/url')).toBe('/mypath/some/relative/url');
+    });
+
+    it('encodes certain character in the url', () => {
+      expect(urlUtils.parseUrlPathname('test="a b"')).toBe('/test=%22a%20b%22');
+    });
+  });
+
   describe('webIDEUrl', () => {
     afterEach(() => {
       gon.relative_url_root = '';
@@ -636,7 +657,7 @@ describe('URL utility', () => {
     `('returns "$expectation" with "$protocol" protocol', ({ protocol, expectation }) => {
       setWindowLocation(`${protocol}//example.com`);
 
-      expect(urlUtils.getWebSocketProtocol()).toEqual(expectation);
+      expect(urlUtils.getWebSocketProtocol()).toBe(expectation);
     });
   });
 
@@ -646,7 +667,7 @@ describe('URL utility', () => {
 
       const path = '/lorem/ipsum?a=bc';
 
-      expect(urlUtils.getWebSocketUrl(path)).toEqual('ws://example.com/lorem/ipsum?a=bc');
+      expect(urlUtils.getWebSocketUrl(path)).toBe('ws://example.com/lorem/ipsum?a=bc');
     });
   });
 
@@ -696,7 +717,7 @@ describe('URL utility', () => {
     it('should return valid parameter', () => {
       setWindowLocation('?scope=all&p=2');
 
-      expect(getParameterByName('p')).toEqual('2');
+      expect(getParameterByName('p')).toBe('2');
       expect(getParameterByName('scope')).toBe('all');
     });
 
@@ -737,7 +758,7 @@ describe('URL utility', () => {
     it('converts search query object back into a search query', () => {
       const searchQueryObject = { one: '1', two: '2' };
 
-      expect(urlUtils.objectToQuery(searchQueryObject)).toEqual('one=1&two=2');
+      expect(urlUtils.objectToQuery(searchQueryObject)).toBe('one=1&two=2');
     });
 
     it('returns empty string when `params` is undefined, null or empty string', () => {
@@ -833,15 +854,15 @@ describe('URL utility', () => {
     it('adds new params as query string', () => {
       const url = 'https://gitlab.com/test';
 
-      expect(
-        urlUtils.setUrlParams({ group_id: 'gitlab-org', project_id: 'my-project' }, url),
-      ).toEqual('https://gitlab.com/test?group_id=gitlab-org&project_id=my-project');
+      expect(urlUtils.setUrlParams({ group_id: 'gitlab-org', project_id: 'my-project' }, url)).toBe(
+        'https://gitlab.com/test?group_id=gitlab-org&project_id=my-project',
+      );
     });
 
     it('updates an existing parameter', () => {
       const url = 'https://gitlab.com/test?group_id=gitlab-org&project_id=my-project';
 
-      expect(urlUtils.setUrlParams({ project_id: 'gitlab-test' }, url)).toEqual(
+      expect(urlUtils.setUrlParams({ project_id: 'gitlab-test' }, url)).toBe(
         'https://gitlab.com/test?group_id=gitlab-org&project_id=gitlab-test',
       );
     });
@@ -849,7 +870,7 @@ describe('URL utility', () => {
     it("removes the project_id param when it's value is null", () => {
       const url = 'https://gitlab.com/test?group_id=gitlab-org&project_id=my-project';
 
-      expect(urlUtils.setUrlParams({ project_id: null }, url)).toEqual(
+      expect(urlUtils.setUrlParams({ project_id: null }, url)).toBe(
         'https://gitlab.com/test?group_id=gitlab-org',
       );
     });
@@ -857,7 +878,7 @@ describe('URL utility', () => {
     it('adds parameters from arrays', () => {
       const url = 'https://gitlab.com/test';
 
-      expect(urlUtils.setUrlParams({ labels: ['foo', 'bar'] }, url)).toEqual(
+      expect(urlUtils.setUrlParams({ labels: ['foo', 'bar'] }, url)).toBe(
         'https://gitlab.com/test?labels=foo&labels=bar',
       );
     });
@@ -865,13 +886,13 @@ describe('URL utility', () => {
     it('removes parameters from empty arrays', () => {
       const url = 'https://gitlab.com/test?labels=foo&labels=bar';
 
-      expect(urlUtils.setUrlParams({ labels: [] }, url)).toEqual('https://gitlab.com/test');
+      expect(urlUtils.setUrlParams({ labels: [] }, url)).toBe('https://gitlab.com/test');
     });
 
     it('removes parameters from empty arrays while keeping other parameters', () => {
       const url = 'https://gitlab.com/test?labels=foo&labels=bar&unrelated=unrelated';
 
-      expect(urlUtils.setUrlParams({ labels: [] }, url)).toEqual(
+      expect(urlUtils.setUrlParams({ labels: [] }, url)).toBe(
         'https://gitlab.com/test?unrelated=unrelated',
       );
     });
@@ -879,7 +900,7 @@ describe('URL utility', () => {
     it('adds parameters from arrays when railsArraySyntax=true', () => {
       const url = 'https://gitlab.com/test';
 
-      expect(urlUtils.setUrlParams({ labels: ['foo', 'bar'] }, url, false, true)).toEqual(
+      expect(urlUtils.setUrlParams({ labels: ['foo', 'bar'] }, url, false, true)).toBe(
         'https://gitlab.com/test?labels%5B%5D=foo&labels%5B%5D=bar',
       );
     });
@@ -887,7 +908,7 @@ describe('URL utility', () => {
     it('removes parameters from empty arrays when railsArraySyntax=true', () => {
       const url = 'https://gitlab.com/test?labels%5B%5D=foo&labels%5B%5D=bar';
 
-      expect(urlUtils.setUrlParams({ labels: [] }, url, false, true)).toEqual(
+      expect(urlUtils.setUrlParams({ labels: [] }, url, false, true)).toBe(
         'https://gitlab.com/test',
       );
     });
@@ -895,7 +916,7 @@ describe('URL utility', () => {
     it('decodes URI when decodeURI=true', () => {
       const url = 'https://gitlab.com/test';
 
-      expect(urlUtils.setUrlParams({ labels: ['foo', 'bar'] }, url, false, true, true)).toEqual(
+      expect(urlUtils.setUrlParams({ labels: ['foo', 'bar'] }, url, false, true, true)).toBe(
         'https://gitlab.com/test?labels[]=foo&labels[]=bar',
       );
     });
@@ -903,7 +924,7 @@ describe('URL utility', () => {
     it('removes all existing URL params and sets a new param when cleanParams=true', () => {
       const url = 'https://gitlab.com/test?group_id=gitlab-org&project_id=my-project';
 
-      expect(urlUtils.setUrlParams({ foo: 'bar' }, url, true)).toEqual(
+      expect(urlUtils.setUrlParams({ foo: 'bar' }, url, true)).toBe(
         'https://gitlab.com/test?foo=bar',
       );
     });

spec/frontend/merge_request_tabs_spec.js

@@ -4,6 +4,7 @@ import initMrPage from 'helpers/init_vue_mr_page_helper';
 import axios from '~/lib/utils/axios_utils';
 import MergeRequestTabs from '~/merge_request_tabs';
 import '~/lib/utils/common_utils';
+import '~/lib/utils/url_utility';
 
 jest.mock('~/lib/utils/webpack', () => ({
   resetServiceWorkersPublicPath: jest.fn(),