fix(b-form-file): fix value prop validation when using directory mode (…

…fixes #4912) (#4913)

* fix(b-form-file): fix value prop validation when using directory mode


Fixes #4912

* Update form-file.js

* Update form-file.js

* Update form-file.js

* Update form-file.js

* Update form-file.js

* Update form-file.js

* Update form-file.js

Co-authored-by: Jacob Müller <jacob.mueller.elz@gmail.com>

src/components/form-file/form-file.js

@@ -12,11 +12,17 @@ import formStateMixin from '../../mixins/form-state'
 import idMixin from '../../mixins/id'
 import normalizeSlotMixin from '../../mixins/normalize-slot'
 
+// --- Constants ---
+
 const NAME = 'BFormFile'
 
 const VALUE_EMPTY_DEPRECATED_MSG =
   'Setting "value"/"v-model" to an empty string for reset is deprecated. Set to "null" instead.'
 
+// --- Helper methods ---
+
+const isValidValue = value => isFile(value) || (isArray(value) && value.every(v => isValidValue(v)))
+
 // @vue/component
 export const BFormFile = /*#__PURE__*/ Vue.extend({
   name: NAME,
@@ -34,17 +40,13 @@ export const BFormFile = /*#__PURE__*/ Vue.extend({
     value: {
       type: [File, Array],
       default: null,
-      validator: val => {
+      validator: value => {
         /* istanbul ignore next */
-        if (val === '') {
+        if (value === '') {
           warn(VALUE_EMPTY_DEPRECATED_MSG, NAME)
           return true
         }
-        return (
-          isUndefinedOrNull(val) ||
-          isFile(val) ||
-          (isArray(val) && (val.length === 0 || val.every(isFile)))
-        )
+        return isUndefinedOrNull(value) || isValidValue(value)
       }
     },
     accept: {