improve

lib/core/util.js

@@ -93,10 +93,6 @@ function parseURL (url) {
     throw new InvalidArgumentError('Invalid URL: The URL argument must be a non-null object.')
   }
 
-  if (!isHttpOrHttpsPrefixed(url.origin || url.protocol)) {
-    throw new InvalidArgumentError('Invalid URL protocol: the URL must start with `http:` or `https:`.')
-  }
-
   if (!(url instanceof URL)) {
     if (url.port != null && url.port !== '' && isValidPort(url.port) === false) {
       throw new InvalidArgumentError('Invalid URL: port must be a valid integer or a string representation of an integer.')
@@ -118,6 +114,10 @@ function parseURL (url) {
       throw new InvalidArgumentError('Invalid URL origin: the origin must be a string or null/undefined.')
     }
 
+    if (!isHttpOrHttpsPrefixed(url.origin || url.protocol)) {
+      throw new InvalidArgumentError('Invalid URL protocol: the URL must start with `http:` or `https:`.')
+    }
+
     const port = url.port != null
       ? url.port
       : (url.protocol === 'https:' ? 443 : 80)
@@ -139,7 +139,11 @@ function parseURL (url) {
     // From https://developer.mozilla.org/en-US/docs/Web/API/URL/URL:
     // If first parameter is a relative URL, second param is required, and will be used as the base URL.
     // If first parameter is an absolute URL, a given second param will be ignored.
-    url = new URL(`${origin || ''}${path || ''}`)
+    return new URL(`${origin}${path}`)
+  }
+
+  if (!isHttpOrHttpsPrefixed(url.origin || url.protocol)) {
+    throw new InvalidArgumentError('Invalid URL protocol: the URL must start with `http:` or `https:`.')
   }
 
   return url

test/node-test/client-errors.js

@@ -386,7 +386,7 @@ test('invalid options throws', (t, done) => {
     assert.ok(0)
   } catch (err) {
     assert.ok(err instanceof errors.InvalidArgumentError)
-    assert.strictEqual(err.message, 'Invalid URL protocol: the URL must start with `http:` or `https:`.')
+    assert.strictEqual(err.message, 'Invalid URL hostname: the hostname must be a string or null/undefined.')
   }
 
   try {

test/util.js

@@ -233,13 +233,22 @@ describe('parseURL', () => {
         parseURL({ protocol: 'http:', hostname: 'www.example.com', origin: undefined })
       })
       test('throws if origin is not as string', () => {
-        throws(() => parseURL({ protocol: 'http:', origin: 1 }), new InvalidArgumentError('Invalid URL protocol: the URL must start with `http:` or `https:`.'))
+        throws(() => parseURL({ protocol: 'http:', origin: 1 }), new InvalidArgumentError('Invalid URL origin: the origin must be a string or null/undefined.'))
       })
       test('doesn\'t throw if origin is a string', () => {
         parseURL({ protocol: 'http:', origin: 'https://www.example.com' })
       })
       test('removes trailing /', () => {
-        parseURL({ protocol: 'http:', origin: 'https://www.example.com/' })
+        strictEqual(parseURL({ protocol: 'http:', origin: 'https://www.example.com/' }).origin, 'https://www.example.com')
+      })
+    })
+
+    describe('protocol', () => {
+      test('throws if protocol is not http: or https: and no origin is defined', () => {
+        throws(() => parseURL({ protocol: 'wss:', hostname: 'www.example.com', path: '' }))
+      })
+      test('doesn\'t throw when origin is not provided', () => {
+        strictEqual(parseURL({ protocol: 'http:', hostname: 'www.example.com', path: '' }).origin, 'http://www.example.com')
       })
     })
   })