Lab 25: Redux with React

Objectives

• Refactor the Page (container) component to use React Redux Hooks
• Refactor the Form component to dispatch an action

Steps

Refactor the Page (container) component to use React Redux Hooks

1. Remove the Page (container) component's local state and replace with Redux state using useSelector. Also, get a reference to the Store's dispatch function using useDispatch so we can dispatch actions.

   src\projects\ProjectsPage.js

   Make sure you are in ProjectsPage.js not ProjectPage.js.

   - import React, { useState, useEffect } from 'react';
   + import React, { useEffect } from 'react';
   import ProjectList from './ProjectList';
   - import { Project } from './Project';
   + import { useSelector, useDispatch } from 'react-redux';
   
   function ProjectsPage() {
   -  const [projects, setProjects] = useState<Project[]>([]);
   -  const [loading, setLoading] = useState(false);
   -  const [error, setError] = useState(undefined);
   -  const [currentPage, setCurrentPage] = useState(1);
   
   +  const loading = useSelector(
   +    (appState) => appState.projectState.loading
   +  );
   +  const projects = useSelector(
   +    (appState) => appState.projectState.projects
   +  );
   +  const error = useSelector(
   +    (appState) => appState.projectState.error
   +  );
   +  const currentPage = useSelector(
   +    (appState) => appState.projectState.page
   +  );
   +  const dispatch = useDispatch();
   
   ...
   }

2. Replace state setter function calls and API calls with calls to dispatch passing action creators. Also, remove the onSave function and stop passing it as a prop to the <ProjectList/> component.

   src\projects\ProjectsPage.js

   ...
   - import { Project } from './Project';
   - import { projectAPI } from './projectAPI';
   + import { loadProjects } from './state/projectActions';
   
   function ProjectsPage() {
     ...
     const dispatch = useDispatch();
   
   -  useEffect(() => {
   -    setLoading(true);
   -    projectAPI
   -      .get(currentPage)
   -      .then((data) => {
   -        setLoading(false);
   -        if (currentPage === 1) {
   -          setProjects(data);
   -        } else {
   -          setProjects((projects) => [...projects, ...data]);
   -        }
   -      })
   -      .catch((e) => {
   -        setLoading(false);
   -        setError(e.message);
   -      });
   -  }, [currentPage]);
   
   +  useEffect(() => {
   +    dispatch(loadProjects(1));
   +  }, [dispatch]);
   
     const handleMoreClick = () => {
   -    setCurrentPage((currentPage) => currentPage + 1);
   +    dispatch(loadProjects(currentPage + 1));
     };
   
   -  const saveProject = (project) => {
   -    projectAPI
   -      .put(project)
   -      .then((updatedProject) => {
   -        let updatedProjects = projects.map((p) => {
   -          return p.id === project.id ? project : p;
   -        });
   -        setProjects(updatedProjects);
   -      })
   -      .catch((e) => {
   -        setError(e.message);
   -      });
   -  };
   
     return (
       <Fragment>
         ...
   -      <ProjectList onSave={saveProject} projects={projects} />
   +      <ProjectList projects={projects} />
         ...
       </Fragment>
     );
   }
   ...

3. Provide the store.

   src\App.js

   import ProjectPage from './projects/ProjectPage';
   + import { Provider } from 'react-redux';
   + import { store } from './state';
   
   function App() {
     return (
   +    <Provider store={store}>
         <Router>
           <header className="sticky">
             <span className="logo">
               <img src="/assets/logo-3.svg" alt="logo" width="49" height="99" />
             </span>
             <NavLink to="/"  className="button rounded">
               <span className="icon-home"></span>
               Home
             </NavLink>
             <NavLink to="/projects/" className="button rounded">
               Projects
             </NavLink>
           </header>
           <div className="container">
             <Routes>
               <Route path="/"  component={HomePage} />
               <Route path="/projects"  component={ProjectsPage} />
               <Route path="/projects/:id" component={ProjectPage} />
             </Routes>
           </div>
         </Router>
   +   </Provider>
     );
   };
   
   export default App;

Refactor the Form component to dispatch an action

1. Refactor the Form component so it dispatches the saveProject action instead of receiving the function as a prop.

   src\projects\ProjectForm.js

   import React, { SyntheticEvent, useState } from 'react';
   + import { useDispatch } from 'react-redux';
   import { Project } from './Project';
   + import { saveProject } from './state/projectActions';
   
   function ProjectForm({
     project: initialProject,
   - onSave,
     onCancel,
   }) {
     const [project, setProject] = useState(initialProject);
     const [errors, setErrors] = useState({
       name: '',
       description: '',
       budget: '',
     });
   
   +  const dispatch = useDispatch();
   
     const handleSubmit = (event) => {
       event.preventDefault();
       if (!isValid()) return;
   -    onSave(project);
   +    dispatch(saveProject(project));
     };
   
     const handleChange = (event) => {
       ...
     };
   
     function validate(project) {
     ...
     }
   
     function isValid() {
       ...
     }
   
     return (
       <form className="input-group vertical" onSubmit={handleSubmit}>
       ...
       </form>
     );
   }
   
   ProjectForm.propTypes = {
   -  onSave: PropTypes.func.isRequired,
     onCancel: PropTypes.func.isRequired
   };
   export default ProjectForm;

2. Provide the store.

   • This was already done in src\App.js because it is inherited from the parent Page component: Page =>List=>Form.

3. In the ProjectList component, remove onSave in the propTypes definition and update the component to not pass onSave to <ProjectForm> as it is now dispatches this action itself after importing it.

   src\Projects\ProjectList.js

   import React, { useState } from 'react';
   import { Project } from './Project';
   import ProjectCard from './ProjectCard';
   import ProjectForm from './ProjectForm';
   
   - function ProjectList({ projects, onSave }) {
   + function ProjectList({ projects }) {
     const [projectBeingEdited, setProjectBeingEdited] = useState({});
   
     const handleEdit = (project) => {
       setProjectBeingEdited(project);
     };
   
     const cancelEditing = () => {
       setProjectBeingEdited({});
     };
   
     return (
       <div className="row">
         {projects.map((project) => (
           <div key={project.id} className="cols-sm">
             {project === projectBeingEdited ? (
               <ProjectForm project={project}
   -             onSave={onSave}
                 onCancel={cancelEditing} />
             ) : (
               <ProjectCard project={project} onEdit={handleEdit} />
             )}
           </div>
         ))}
       </div>
     );
    }
   
    ProjectList.propTypes = {
      projects: PropTypes.arrayOf(PropTypes.instanceOf(Project)).isRequired,
   -  onSave: PropTypes.func.isRequired
    };
   export default ProjectList;

4. Verify the application still works including loading and updating the projects.

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✔ You have completed Lab 25

Please let the instructor know you have completed this lab before continuing to the bonus exercise.

Bonus Exercise (optional)

Do this exercise in your own time outside of class or while waiting for other students to finish the labs.

Now that you have the ProjectsPage (plural) refactored to use Redux, use what you have learned to change the ProjectPage (singular) code to use Redux as well.

Not giving you specific directions on how to do this is intentional at this point. It is time to see if you can apply what you learned without specific guidance. Tip: Remember, it is perfectly valid to reference your existing code from the last few labs to complete this exercise.