Create model infinite scroll

Author: francoism90

src/Models/Concerns/WithScroll.php

@@ -0,0 +1,130 @@
+<?php
+
+namespace Foxws\WireUse\Models\Concerns;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Collection;
+use Livewire\Attributes\Computed;
+use Livewire\Attributes\Locked;
+
+trait WithScroll
+{
+    #[Locked]
+    public Collection $models;
+
+    #[Locked]
+    public int $fetchCount = 0;
+
+    public function bootWithScroll(): void
+    {
+        data_set($this, 'models', collect(), false);
+    }
+
+    public function mountWithScroll(): void
+    {
+        if ($this->models->isEmpty()) {
+            $this->fetch();
+        }
+    }
+
+    #[Computed(persist: true, seconds: 3600)]
+    public function items(): Collection
+    {
+        return $this->models;
+    }
+
+    /**
+     * This will fetch and merge the items.
+     */
+    public function fetch(): void
+    {
+        if (! $this->isFetchable()) {
+            return;
+        }
+
+        $items = $this->getMergeCandidates();
+
+        if ($items->isNotEmpty()) {
+            $this->mergeScrollItems($items);
+        }
+
+        $this->fetchCount++;
+    }
+
+    /**
+     * This will release the current items cache.
+     */
+    public function refresh(): void
+    {
+        unset($this->items);
+
+        $this->dispatch('$refresh');
+    }
+
+    /**
+     * This should be called to clear the model instances.
+     */
+    public function clear(): void
+    {
+        $this->reset('fetchCount');
+
+        $this->models = collect();
+
+        unset($this->items);
+    }
+
+    public function isFetchable(): bool
+    {
+        return is_null($this->getFetchLimits()) || $this->fetchCount < $this->getFetchLimits();
+    }
+
+    /**
+     * This should be called to merge the model instances.
+     */
+    protected function mergeScrollItems(Collection $items): void
+    {
+        $items = $items
+            ->take($this->getCandidatesLimit())
+            ->reject(fn ($item) => ! $item instanceof Model)
+            ->filter()
+            ->all();
+
+        $this->models = $this->models
+            ->merge($items)
+            ->unique($this->getItemUniqueKey());
+
+        $this->refresh();
+    }
+
+    /**
+     * This should return the model instances that will be merged.
+     */
+    protected function getMergeCandidates(): Collection
+    {
+        return collect();
+    }
+
+    /**
+     * This will ensure that the items are unique, to prevent any Livewire key conflicts.
+     */
+    protected function getItemUniqueKey(): ?string
+    {
+        return 'id';
+    }
+
+    /**
+     * This a limit that will used when fetching and merging items.
+     */
+    protected function getCandidatesLimit(): int
+    {
+        return 16;
+    }
+
+    /**
+     * How many times it is possible to call fetch.
+     */
+    protected function getFetchLimits(): ?int
+    {
+        return null;
+    }
+}