From 82815b6d9a6494ae3d752e82e670dd89982e0d6a Mon Sep 17 00:00:00 2001
From: Tudor Stanciu <tudor.stanciu94@gmail.com>
Date: Sun, 12 Apr 2020 02:10:57 +0300
Subject: [PATCH] Optimistic delete

---
 src/components/courses/CourseList.js  | 14 ++++++++++++--
 src/components/courses/CoursesPage.js | 18 ++++++++++++++++--
 src/redux/actions/actionTypes.js      |  7 +++++++
 src/redux/actions/courseActions.js    | 13 +++++++++++++
 src/redux/reducers/courseReducer.js   |  3 +++
 5 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/src/components/courses/CourseList.js b/src/components/courses/CourseList.js
index 40cfe04..7ae652b 100644
--- a/src/components/courses/CourseList.js
+++ b/src/components/courses/CourseList.js
@@ -2,7 +2,7 @@ import React from "react";
 import PropTypes from "prop-types";
 import { Link } from "react-router-dom";
 
-const CourseList = ({ courses }) => (
+const CourseList = ({ courses, onDeleteClick }) => (
   <table className="table">
     <thead>
       <tr>
@@ -10,6 +10,7 @@ const CourseList = ({ courses }) => (
         <th>Title</th>
         <th>Author</th>
         <th>Category</th>
+        <th />
       </tr>
     </thead>
     <tbody>
@@ -29,6 +30,14 @@ const CourseList = ({ courses }) => (
             </td>
             <td>{course.authorName}</td>
             <td>{course.category}</td>
+            <td>
+              <button
+                className="btn btn-outline-danger"
+                onClick={() => onDeleteClick(course)}
+              >
+                Delete
+              </button>
+            </td>
           </tr>
         );
       })}
@@ -37,7 +46,8 @@ const CourseList = ({ courses }) => (
 );
 
 CourseList.propTypes = {
-  courses: PropTypes.array.isRequired
+  courses: PropTypes.array.isRequired,
+  onDeleteClick: PropTypes.func.isRequired
 };
 
 export default CourseList;
diff --git a/src/components/courses/CoursesPage.js b/src/components/courses/CoursesPage.js
index 0b7cf5c..6e73725 100644
--- a/src/components/courses/CoursesPage.js
+++ b/src/components/courses/CoursesPage.js
@@ -7,6 +7,7 @@ import { bindActionCreators } from "redux";
 import CourseList from "./CourseList";
 import { Redirect } from "react-router-dom";
 import Spinner from "../common/Spinner";
+import { toast } from "react-toastify";
 
 class CoursesPage extends React.Component {
   state = {
@@ -29,6 +30,15 @@ class CoursesPage extends React.Component {
     }
   }
 
+  handleDeleteCourse = async (course) => {
+    toast.success("Course deleted");
+    try {
+      await this.props.actions.deleteCourse(course);
+    } catch (error) {
+      toast.error("Delete failed. " + error.message, { autoClose: false });
+    }
+  };
+
   render() {
     return (
       <>
@@ -46,7 +56,10 @@ class CoursesPage extends React.Component {
               Add Course
             </button>
 
-            <CourseList courses={this.props.courses} />
+            <CourseList
+              courses={this.props.courses}
+              onDeleteClick={this.handleDeleteCourse}
+            />
           </>
         )}
       </>
@@ -83,7 +96,8 @@ function mapDispatchToProps(dispatch) {
     actions: bindActionCreators(
       {
         loadCourses: courseActions.loadCourses,
-        loadAuthors: authorActions.loadAuthors
+        loadAuthors: authorActions.loadAuthors,
+        deleteCourse: courseActions.deleteCourse
       },
       dispatch
     )
diff --git a/src/redux/actions/actionTypes.js b/src/redux/actions/actionTypes.js
index 4fe8b31..612614e 100644
--- a/src/redux/actions/actionTypes.js
+++ b/src/redux/actions/actionTypes.js
@@ -5,3 +5,10 @@ export const CREATE_COURSE_SUCCESS = "CREATE_COURSE_SUCCESS";
 export const UPDATE_COURSE_SUCCESS = "UPDATE_COURSE_SUCCESS";
 export const BEGIN_API_CALL = "BEGIN_API_CALL";
 export const API_CALL_ERROR = "API_CALL_ERROR";
+
+// By convention, actions that end in "_SUCCESS" are assumed to have been the result of a completed
+// API call. But since we're doing an optimistic delete, we're hiding loading state.
+// So this action name deliberately omits the "_SUCCESS" suffix.
+// If it had one, our apiCallsInProgress counter would be decremented below zero
+// because we're not incrementing the number of apiCallInProgress when the delete request begins.
+export const DELETE_COURSE_OPTIMISTIC = "DELETE_COURSE_OPTIMISTIC";
diff --git a/src/redux/actions/courseActions.js b/src/redux/actions/courseActions.js
index be5f5a3..b59760c 100644
--- a/src/redux/actions/courseActions.js
+++ b/src/redux/actions/courseActions.js
@@ -14,6 +14,10 @@ export function updateCourseSuccess(course) {
   return { type: types.UPDATE_COURSE_SUCCESS, course };
 }
 
+export function deleteCourseOptimistic(course) {
+  return { type: types.DELETE_COURSE_OPTIMISTIC, course };
+}
+
 export function loadCourses() {
   return function (dispatch) {
     dispatch(beginApiCall());
@@ -46,3 +50,12 @@ export function saveCourse(course) {
       });
   };
 }
+
+export function deleteCourse(course) {
+  return function (dispatch) {
+    // Doing optimistic delete, so not dispatching begin/end api call
+    // actions, or apiCallError action since we're not showing the loading status for this.
+    dispatch(deleteCourseOptimistic(course));
+    return courseApi.deleteCourse(course.id);
+  };
+}
diff --git a/src/redux/reducers/courseReducer.js b/src/redux/reducers/courseReducer.js
index c1bf7f9..dcdbae5 100644
--- a/src/redux/reducers/courseReducer.js
+++ b/src/redux/reducers/courseReducer.js
@@ -14,6 +14,9 @@ export default function courseReducer(state = initialState.courses, action) {
         course.id === action.course.id ? action.course : course
       );
 
+    case types.DELETE_COURSE_OPTIMISTIC:
+      return state.filter((course) => course.id !== action.course.id);
+
     default:
       return state;
   }