fixes URL validation method for cross-browser support

In Firefox this will throw an Error:

```
new URL("https://www. example .com ")
```

In Chrome the same action will result in:

```
https://www.%20example%20.com
```

As a result the try/catch pattern used for validation rarely flagged
links on Chrome.

The approach in this commit uses a lenient regular expression to
validate URLs. A URL just needs a protocol, a domain, and optionally a
path. The domain and protocol have a limited character set.

lib/validators/built-in/invalid-links.js

@@ -1,5 +1,4 @@
 import _ from 'lodash';
-import * as validUrl from 'valid-url';
 import {
   forEachComponent, forEachField, labelComponent, getPreviewText
 } from '../helpers';
@@ -20,6 +19,26 @@ const COMPONENTS = [
  */
 const isHash = (url) => (/^#/u).test(url);
 
+/**
+ * Confirms that a URL loosely matches one of the following formats:
+ * - {protocol}://{domain}/*
+ * - mailto:{address}
+ * - #{anchor}
+ *
+ * Note: We cannot use a try/catch on 'new URL' here because some browsers
+ * will automatically encode spaces. Kiln prepends values with "https://" when
+ * an explicit protocol is not provided. These two behaviors combined result
+ * in almost *any* value getting coerced to something that will pass validation.
+ *
+ * @param {string} url: The href value of a link.
+ * @returns {boolean} true if link is valid URL, else false.
+ */
+const isValid = (url) => (
+  (/^\w+:\/\/[^\s/$.?#].[^\s]*$/u).test(url) // {protocol}://{domain}/*
+  || (/^mailto:[^\s]+$/u).test(url) // mailto:{address}
+  || (/^#[^\s+]/u).test(url) // #{anchor}
+);
+
 /**
  * Collects all invalid links from the page state and returns
  * an array of validation errors.
@@ -37,7 +56,7 @@ export function validate(state) {
       [...val.matchAll(/href="([^"]+)"[^>]*>([^<]*)/gu)]
         .map(match => [match[1], match[2]])
         .filter(([linkUrl]) => !isHash(linkUrl))
-        .filter(([linkUrl]) => !validUrl.isUri(linkUrl))
+        .filter(([linkUrl]) => !isValid(linkUrl))
         .map(([, linkText]) => ({
           uri,
           field: _.head(field.path.split('.')),

lib/validators/built-in/invalid-links.test.js

@@ -59,6 +59,56 @@ describe('validators: invalid-links', () => {
       })).toEqual([]);
     });
 
+    test('passes if field with mailto link', () => {
+      expect(fn({
+        components: {
+          [uri]: { a: '<a href="mailto:[email protected]">Lorem ipsum dolor sit amet</a>, consectetur adipisicing elit' }
+        },
+        schemas: {
+          [name]: {
+            a: {
+              _has: ['text']
+            }
+          }
+        }
+      })).toEqual([]);
+    });
+
+    test('passes if field with ftp link', () => {
+      expect(fn({
+        components: {
+          [uri]: { a: '<a href="ftp://1.1.1.1:21/test">Lorem ipsum dolor sit amet</a>, consectetur adipisicing elit' }
+        },
+        schemas: {
+          [name]: {
+            a: {
+              _has: ['text']
+            }
+          }
+        }
+      })).toEqual([]);
+    });
+
+    test('fails if field relative link', () => {
+      expect(fn({
+        components: {
+          [uri]: { a: '<a href="/subscribe">Lorem ipsum dolor sit amet</a>, consectetur adipisicing elit' }
+        },
+        schemas: {
+          [name]: {
+            a: {
+              _has: ['text']
+            }
+          }
+        }
+      })).toEqual([{
+        uri,
+        field: 'a',
+        location: 'Paragraph',
+        preview: 'Lorem ipsum dolor sit amet…'
+      }]);
+    });
+
     test('fails if field with invalid link', () => {
       expect(fn({
         components: {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "clay-kiln",
-  "version": "8.18.0",
+  "version": "8.17.0",
   "description": "Editor tools for Clay",
   "template": "template.handlebars",
   "scripts": {
@@ -13,9 +13,8 @@
     "test-local": "BABEL_ENV=test npm run jest -- --watch",
     "build": "BABEL_ENV=build webpack",
     "watch": "BABEL_ENV=build webpack -w",
-    "prepublishOnly": "BABEL_ENV=build webpack -p",
-    "generate-actions": "jsdoc2md --files lib/**/actions.js > docs/vuex-actions.md",
-    "release": "./.circleci/scripts/release.sh"
+    "prepublishOnly": "BABEL_ENV=build webpack -p && npm run generate-actions",
+    "generate-actions": "jsdoc2md --files lib/**/actions.js > docs/vuex-actions.md"
   },
   "repository": {
     "type": "git",
@@ -151,7 +150,6 @@
     "striptags": "^3.1.0",
     "style-loader": "^0.19.0",
     "url-parse": "^1.4.4",
-    "valid-url": "^1.0.9",
     "velocity-animate": "^1.5.0",
     "vue": "^2.5.9",
     "vue-async-computed": "^3.3.1",

webpack.config.js

@@ -93,7 +93,7 @@ module.exports = {
   module: {
     rules: [{
       // todo: remove vue-unit (and update vue-unit dep) once vue-unit hits 0.3.0
-      test: /node_modules\/(@tom-kitchin\/vue-unit|keen-ui|striptags|clayutils|valid-url)\//,
+      test: /node_modules\/(@tom-kitchin\/vue-unit|keen-ui|striptags|clayutils)\//,
       loader: 'babel-loader'
     }, {
       test: /\.js$/,