Fixes #5781

Signed-off-by: soupette <cyril.lpz@gmail.com>

packages/strapi-plugin-content-type-builder/admin/src/containers/FormModal/utils/forms.js

@@ -503,6 +503,8 @@ const forms = {
           ];
 
           items = uidItems;
+        } else if (type === 'json') {
+          items.splice(0, 1);
         }
 
         if (!ATTRIBUTES_THAT_DONT_HAVE_MIN_MAX_SETTINGS.includes(type)) {

packages/strapi-plugin-content-type-builder/controllers/validation/common.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const yup = require('yup');
+const _ = require('lodash');
 
 const validators = {
   required: yup.boolean(),
@@ -80,11 +81,34 @@ const isValidRegExpPattern = {
   test: val => val === '' || new RegExp(val),
 };
 
+const isValidDefaultJSON = {
+  name: 'isValidDefaultJSON',
+  message: '${path} is not a valid JSON',
+  test: val => {
+    if (val === undefined) {
+      return true;
+    }
+
+    if (_.isNumber(val) || _.isNull(val) || _.isObject(val) || _.isArray(val)) {
+      return true;
+    }
+
+    try {
+      JSON.parse(val);
+
+      return true;
+    } catch (err) {
+      return false;
+    }
+  },
+};
+
 module.exports = {
   validators,
   areEnumValuesUnique,
   isValidCollectionName,
   isValidCategoryName,
+  isValidDefaultJSON,
   isValidName,
   isValidIcon,
   isValidKey,

packages/strapi-plugin-content-type-builder/controllers/validation/types.js

@@ -6,6 +6,7 @@ const yup = require('yup');
 const {
   validators,
   areEnumValuesUnique,
+  isValidDefaultJSON,
   isValidName,
   isValidEnum,
   isValidUID,
@@ -112,6 +113,7 @@ const getTypeShape = (attribute, { modelType, attributes } = {}) => {
     }
     case 'json': {
       return {
+        default: yup.mixed().test(isValidDefaultJSON),
         required: validators.required,
         unique: validators.unique,
       };