Implemented minItems repeater property on client & server

Also implemented maxItems on server (previously only client). Fixes https://github.com/octobercms/october/issues/3668

modules/backend/formwidgets/Repeater.php

@@ -1,8 +1,9 @@
 <?php namespace Backend\FormWidgets;
 
+use Lang;
+use ApplicationException;
 use Backend\Classes\FormField;
 use Backend\Classes\FormWidgetBase;
-use ApplicationException;
 
 /**
  * Repeater Form Widget
@@ -37,7 +38,12 @@ class Repeater extends FormWidgetBase
     public $titleFrom = false;
 
     /**
-     * @var int Maximum repeated items allowable.
+     * @var int Minimum items required. Pre-displays those items when not using groups
+     */
+    public $minItems = null;
+
+    /**
+     * @var int Maximum items permitted
      */
     public $maxItems = null;
 
@@ -94,6 +100,7 @@ class Repeater extends FormWidgetBase
             'prompt',
             'sortable',
             'titleFrom',
+            'minItems',
             'maxItems',
         ]);
 
@@ -144,6 +151,7 @@ class Repeater extends FormWidgetBase
         $this->vars['prompt'] = $this->prompt;
         $this->vars['formWidgets'] = $this->formWidgets;
         $this->vars['titleFrom'] = $this->titleFrom;
+        $this->vars['minItems'] = $this->minItems;
         $this->vars['maxItems'] = $this->maxItems;
 
         $this->vars['useGroups'] = $this->useGroups;
@@ -184,6 +192,13 @@ class Repeater extends FormWidgetBase
             }
         }
 
+        if ($this->minItems && count($value) < $this->minItems) {
+            throw new ApplicationException(Lang::get('backend::lang.repeater.min_items_failed', ['name' => $this->fieldName, 'min' => $this->minItems, 'items' => count($value)]));
+        }
+        if ($this->maxItems && count($value) > $this->maxItems) {
+            throw new ApplicationException(Lang::get('backend::lang.repeater.max_items_failed', ['name' => $this->fieldName, 'max' => $this->maxItems, 'items' => count($value)]));
+        }
+
         return array_values($value);
     }
 
@@ -196,6 +211,21 @@ class Repeater extends FormWidgetBase
         $loadedIndexes = $loadedGroups = [];
         $loadValue = $this->getLoadValue();
 
+        // Ensure that the minimum number of items are preinitialized
+        // ONLY DONE WHEN NOT IN GROUP MODE
+        if (!$this->useGroups && $this->minItems > 0) {
+            if (!is_array($loadValue)) {
+                $loadValue = [];
+                for ($i = 0; $i < $this->minItems; $i++) {
+                    $loadValue[$i] = [];
+                }
+            } elseif (count($loadValue) < $this->minItems) {
+                for ($i = 0; $i < ($this->minItems - count($loadValue)); $i++) {
+                    $loadValue[] = [];
+                }
+            }
+        }
+
         if (is_array($loadValue)) {
             foreach ($loadValue as $index => $loadedValue) {
                 $loadedIndexes[] = $index;

modules/backend/formwidgets/repeater/assets/js/repeater.js

@@ -34,6 +34,7 @@
         sortableHandle: '.repeater-item-handle',
         sortableContainer: 'ul.field-repeater-items',
         titleFrom: null,
+        minItems: null,
         maxItems: null
     }
 
@@ -122,6 +123,13 @@
     }
 
     Repeater.prototype.togglePrompt = function () {
+        if (this.options.minItems && this.options.minItems > 0) {
+            var repeatedItems = this.$el.find('> .field-repeater-items > .field-repeater-item').length,
+                $removeItemBtn = this.$el.find('> .field-repeater-items > .field-repeater-item > .repeater-item-remove')
+
+            $removeItemBtn.toggle(repeatedItems > this.options.minItems)
+        }
+
         if (this.options.maxItems && this.options.maxItems > 0) {
             var repeatedItems = this.$el.find('> .field-repeater-items > .field-repeater-item').length,
                 $addItemBtn = this.$el.find('> .field-repeater-add-item')

modules/backend/formwidgets/repeater/partials/_repeater.htm

@@ -1,6 +1,7 @@
 <div class="field-repeater"
      data-control="fieldrepeater"
      <?= $titleFrom ? 'data-title-from="'.$titleFrom.'"' : '' ?>
+     <?= $minItems ? 'data-min-items="'.$minItems.'"' : '' ?>
      <?= $maxItems ? 'data-max-items="'.$maxItems.'"' : '' ?>
      data-sortable-container="#<?= $this->getId('items') ?>"
      data-sortable-handle=".<?= $this->getId('items') ?>-handle">

modules/backend/lang/en/lang.php

@@ -217,6 +217,10 @@ return [
         'remove_confirm' => 'Are you sure?',
         'remove_file' => 'Remove file'
     ],
+    'repeater' => [
+        'min_items_failed' => ':name requires a minimum of :min items, only :items were provided',
+        'max_items_failed' => ':name only allows up to :max items, :items were provided',
+    ],
     'form' => [
         'create_title' => 'New :name',
         'update_title' => 'Edit :name',