From e32aeb1b3d3b8e9a3b3fb4918e41306f0c55d779 Mon Sep 17 00:00:00 2001
From: Adam Rybinski <adam.rybins@gmail.com>
Date: Mon, 1 Nov 2021 16:34:39 +0100
Subject: [PATCH] Create paginationMachine.js

---
 paginationMachine.js | 71 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 paginationMachine.js

diff --git a/paginationMachine.js b/paginationMachine.js
new file mode 100644
index 0000000..a82fe53
--- /dev/null
+++ b/paginationMachine.js
@@ -0,0 +1,71 @@
+import { assign, createMachine } from './deps.js';
+
+const infiniteScrollMachine = createMachine({
+  id: 'infiniteScroll',
+  initial: 'fetchingRowOfData',
+  context: {
+    totalEntries: Infinity,
+    data: []
+  },
+  states: {
+    fetchingRowOfData: {
+      on: {
+        RECEIVED_DATA: {
+          target: 'checkingIfThereIsMoreData',
+          actions: ['assignDataToContext']
+        }
+      },
+      invoke: {
+        src: 'fetchRowOfData',
+        onError: {
+          target: 'idle',
+          actions: 'assignErrorMessageToContext'
+        }
+      }
+    },
+    idle: {
+      exit: ['clearErrorMessage'],
+      on: {
+        SCROLL_TO_BOTTOM: 'fetchingRowOfData'
+      }
+    },
+    checkingIfThereIsMoreData: {
+      always: [{
+        cond: 'thereIsMoreData',
+        target: 'idle'
+      }, {
+        target: 'noMoreDataToFetch'
+      }]
+    },
+    noMoreDataToFetch: {
+      type: 'final'
+    }
+  }
+}, {
+  guards: {
+    thereIsMoreData: context => {
+      return context.totalEntries > context.data.length;
+    }
+  },
+  services: {
+    fetchRowOfData: () => send => {}
+  },
+  actions: {
+    assignDataToContext: assign((context, event) => {
+      if (event.type !== 'RECEIVED_DATA') return {};
+      return {
+        data: [...context.data, ...event.data],
+        totalEntries: event.totalEntries
+      };
+    }),
+    clearErrorMessage: assign(context => ({
+      errorMessage: undefined
+    })),
+    assignErrorMessageToContext: assign((context, event) => {
+      return {
+        errorMessage: event.data?.message || 'An unknown error occurred'
+      };
+    })
+  }
+});
+export default infiniteScrollMachine;