Lab 27: React Query Refactor

Objectives

• Install React Query and React Query Devtools.
• Configure React Query Client provider and React Query Devtools.
• Remove the saveProject function and onSave props.
• Refactor the useProjects custom hook to use React Query's useQuery.
• Use React Query’s isFetching status to show when data is refreshing in the background.
• Create and use a useSaveProject custom hook using React Query’s useMutation.

Steps

Install React Query and React Query Devtools.

1. Start with the Lab 26 solution code.

2. Run the follow commands at a command-prompt or terminal (be sure you are in the keeptrack directory).

   npm

   npm install @tanstack/react-query@4
   npm install @tanstack/react-query-devtools@4

   OR

   yarn

   yard add @tanstack/react-query
   yard add @tanstack/react-query-devtools

Configure React Query Client provider and React Query Devtools.

1. Wrap the App component in a QueryClientProvider and add the ReactQueryDevtools inside of the provider. Also, create a QueryClient and pass it to the QueryClientProvider.

   src/index.tsx

   import ReactDOM from 'react-dom';
   import './index.css';
   import App from './App';
   +import { QueryClientProvider, QueryClient } from '@tanstack/react-query';
   +import { ReactQueryDevtools } from '@tanstack/react-query-devtools';
   
   + const queryClient = new QueryClient();
   
   const root = ReactDOM.createRoot(document.getElementById('root'));
   root.render(
     <React.StrictMode>
   +   <QueryClientProvider client={queryClient}>
         <App />
   +      <ReactQueryDevtools initialIsOpen={false} />
   +    </QueryClientProvider>
     </React.StrictMode>
   );

Remove the saveProject function and onSave props

1. Remove all the code highlighted from the following files

   src/projects/ProjectsPage.tsx

     ...
   
     <ProjectList projects={projects}
   - onSave={saveProject}
     />
   
     ...

   src/projects/ProjectList.tsx

   interface ProjectListProps {
     projects: Project[];
   -  onSave: (project: Project) => void;
   }

   ...
   
   function ProjectList({ projects
   - , onSave
   }: ProjectListProps) {
   
   ...

   <ProjectForm
     project={project}
   -  onSave={onSave}
     onCancel={cancelEditing}
   />

   src/projects/ProjectForm.tsx

   ...
   interface ProjectFormProps {
     project: Project;
   -  onSave: (project: Project) => void;
     onCancel: () => void;
   }
   
   function ProjectForm({
     project: initialProject,
   -  onSave,
     onCancel,
   }: ProjectFormProps) {
   ...

   const handleSubmit = (event: SyntheticEvent) => {
       event.preventDefault();
       if (!isValid()) return;
   -    onSave(project);
     };
   

   We will get the save functionality working again later in the lab.

Refactor the useProjects custom hook to use React Query's useQuery.

We will also use React Query’s isFetching status to show when data is refreshing in the background.

1. DELETE ALL the code in src/projects/projectHooks.ts

2. Add the following code. Notice that is significantly less code.

   src/projects/projectHooks.ts

   import { useState } from 'react';
   import { projectAPI } from './projectAPI';
   import {
     useMutation,
     useQuery,
     useQueryClient,
   } from '@tanstack/react-query';
   import { Project } from './Project';
   
   export function useProjects() {
     const [page, setPage] = useState(0);
     let queryInfo = useQuery({
       queryKey: ['projects', page],
       queryFn: () => projectAPI.get(page + 1),
       keepPreviousData: true,
     });
     console.log(queryInfo);
     return { ...queryInfo, page, setPage };
   }

3. DELETE ALL the code in src/projects/ProjectsPage.tsx.

4. Update the ProjectsPage.tsx to use the React Query based custom hook.

   src/projects/ProjectsPage.tsx

   import React, { useEffect, useState } from 'react';
   import { useProjects } from './projectHooks';
   import ProjectList from './ProjectList';
   
   function ProjectsPage() {
     const {
       data,
       isLoading,
       error,
       isError,
       isFetching,
       page,
       setPage,
       isPreviousData,
     } = useProjects();
   
     return (
       <>
         <h1>Projects</h1>
   
         {data ? (
           <>
             {isFetching && !isLoading && (
               <span className="toast">Refreshing...</span>
             )}
             <ProjectList projects={data} />
             <div className="row">
               <div className="col-sm-4">Current page: {page + 1}</div>
               <div className="col-sm-4">
                 <div className="button-group right">
                   <button
                     className="button "
                     onClick={() => setPage((oldPage) => oldPage - 1)}
                     disabled={page === 0}
                   >
                     Previous
                   </button>
                   <button
                     className="button"
                     onClick={() => {
                       if (!isPreviousData) {
                         setPage((oldPage) => oldPage + 1);
                       }
                     }}
                     disabled={data.length != 10}
                   >
                     Next
                   </button>
                 </div>
               </div>
             </div>
           </>
         ) : isLoading ? (
           <div className="center-page">
             <span className="spinner primary"></span>
             <p>Loading...</p>
           </div>
         ) : isError && error instanceof Error ? (
           <div className="row">
             <div className="card large error">
               <section>
                 <p>
                   <span className="icon-alert inverse "></span>
                   {error.message}
                 </p>
               </section>
             </div>
           </div>
         ) : null}
       </>
     );
   }
   
   export default ProjectsPage;
   
   // this commented code is unnecessary it's just here to show you the pattern
   // return (
   //   <>
   //     <h1>Header</h1>
   //     {data ? (
   //       <p>data</p>
   //     ) : isLoading ? (
   //       <p>Loading...</p>
   //     ) : isError ? (
   //       <p>Error Message</p>
   //     ) : null}
   //   </>
   // );

5. To make it easier to see the pagination change the page size to 10 records. Delay the query to make it easier to see the loading indicator.

   src/projects/projectAPI.tsx

   const projectAPI = {
     get(page = 1,
   -  limit = 20
   +  limit = 10
     ) {
       return (
         fetch(`${url}?_page=${page}&_limit=${limit}&_sort=name`)
           .then(delay(2000))
           .then(checkStatus)
           .then(parseJSON)
           .catch((error: TypeError) => {
             console.log('log client error ' + error);
             throw new Error(
               'There was an error retrieving the projects. Please try again.'
             );
           })
       );
     },

6. Test the projects page and verify that the initial load and pagination work.

Create and use a useSaveProject custom hook using React Query’s useMutation.

1. Add the useSaveProject custom hook.

   src/projects/projectHooks.ts

   // existing code
   ...
   
   export function useSaveProject() {
     const queryClient = useQueryClient();
     return useMutation({
       mutationFn: (project: Project) => projectAPI.put(project),
       onSuccess: () => queryClient.invalidateQueries(['projects']),
     });
   }

2. Update the ProjectForm to use the useSaveProject hook.

   src/projects/ProjectForm.tsx

   import React, { SyntheticEvent, useState } from 'react';
   import { Project } from './Project';
   + import { useSaveProject } from './projectHooks';
   
   ...
   
   function ProjectForm({ project: initialProject,
                         onCancel }: ProjectFormProps) {
   
   ...
   
   +  const { mutate: saveProject, isLoading } = useSaveProject();
     const handleSubmit = (event: SyntheticEvent) => {
       event.preventDefault();
       if (!isValid()) return;
   +   saveProject(project);
     };
   
   ...
   
   return (
       <form className="input-group vertical" onSubmit={handleSubmit}>
   +      {isLoading && <span className="toast">Saving...</span>}
         <label htmlFor="name">Project Name</label>
   
   ...
   
   }
   
   export default ProjectForm;

3. Test the projects page. Edit a project and save it and verify the change works and you see the saving toast indicator near the bottom of the page.

✔ You have completed Lab 27