implements accessibility measures and finishes Link richText element

src/fields/richText/defaultValue.js

@@ -0,0 +1,3 @@
+export default [{
+  children: [{ text: '' }],
+}];

src/fields/validations.js

@@ -1,3 +1,5 @@
+const defaultRichTextValue = require('./richText/defaultValue');
+
 const defaultMessage = 'This field is required.';
 
 const optionsToValidatorMap = {
@@ -92,15 +94,9 @@ const optionsToValidatorMap = {
     return true;
   },
   richText: (value, options) => {
-    //! Need better way to share an empty text node
-    //! it is used here and in field-types/RichText
-    const emptyRichTextNode = [{
-      children: [{ text: '' }],
-    }];
-
     if (options.required) {
-      const blankSlateJSNode = JSON.stringify(emptyRichTextNode);
-      if (value && JSON.stringify(value) !== blankSlateJSNode) return true;
+      const stringifiedDefaultValue = JSON.stringify(defaultRichTextValue);
+      if (value && JSON.stringify(value) !== stringifiedDefaultValue) return true;
       return 'This field is required.';
     }