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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.js​

    import ReactDOM from 'react-dom';
    import './index.css';
    import App from './App';
    import * as serviceWorker from './serviceWorker';
    +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.js​

      ...

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

      ...

    src/projects/ProjectList.js​

    ...

    ProjectList.propTypes = {
      projects: PropTypes.arrayOf(PropTypes.instanceOf(Project)).isRequired,
    -  onSave: PropTypes.func.isRequired,
    };

    export default ProjectList;
    ...

    function ProjectList({ projects
    - , onSave
    }) {

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

    src/projects/ProjectForm.js​

     ...

     function ProjectForm({
       project: initialProject,
    -  onSave,
       onCancel,
     }) {
     ...

     ProjectForm.propTypes = {
       project: PropTypes.instanceOf(Project),
       onCancel: PropTypes.func.isRequired,
    -  onSave: PropTypes.func.isRequired,
     };

     export default ProjectForm;

    const handleSubmit = (event) => {
        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.js

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

    src/projects/projectHooks.js​

    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,
        // staleTime: 5000,
      });
      console.log(queryInfo);
      return { ...queryInfo, page, setPage };
    }

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

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

    src/projects/ProjectsPage.js​

    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.js​

    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) => {
              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.js​

    // existing code
    ...

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

  2. Update the ProjectForm to use the useSaveProject hook.

    src/projects/ProjectForm.js​

    import React, { SyntheticEvent, useState } from 'react';
    import { Project } from './Project';
    + import { useSaveProject } from './projectHooks';

    ...

    function ProjectForm({ project: initialProject,
                          onCancel }) {

    ...

    +  const { mutate: saveProject, isLoading } = useSaveProject();
      const handleSubmit = (event) => {
        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​