You create a little countdown app that is useful either to focus on you breath for some seconds or to count back seconds for whatever need you have.
Learn about state and testing in React
The requirements are the following:
- A counter should be displayed all the time.
- That counter should be initialized to zero.
- A + button should be displayed and should add a second on click.
- A - button should be displayed and should substract a second on click.
- The - button should not substract past zero.
- A start button should be displayed and should start a countdown substracting one unit per second.
- The countdown should finish at 0.
- While the countdown is running the +, - and start buttons should be disabled.
- The +, -, and start buttons should be re-enabled when the countdown is over.
As sometimes it is difficult to validate certain situations just by rendering the components I suggest trying to apply also mutation testing with Stryker that works well with React.
This project was bootstrapped with Create React App.
In the project directory, you can run:
Runs the app in the development mode.
Open http://localhost:3000 to view it in your browser.
The page will reload when you make changes.
You may also see any lint errors in the console.
Launches the test runner in the interactive watch mode.
See the section about running tests for more information.
Builds the app for production to the build
folder.
It correctly bundles React in production mode and optimizes the build for the best performance.
The build is minified and the filenames include the hashes.
Your app is ready to be deployed!
See the section about deployment for more information.
Note: this is a one-way operation. Once you eject
, you can't go back!
If you aren't satisfied with the build tool and configuration choices, you can eject
at any time. This command will remove the single build dependency from your project.
Instead, it will copy all the configuration files and the transitive dependencies (webpack, Babel, ESLint, etc) right into your project so you have full control over them. All of the commands except eject
will still work, but they will point to the copied scripts so you can tweak them. At this point you're on your own.
You don't have to ever use eject
. The curated feature set is suitable for small and middle deployments, and you shouldn't feel obligated to use this feature. However we understand that this tool wouldn't be useful if you couldn't customize it when you are ready for it.
You can learn more in the Create React App documentation.
To learn React, check out the React documentation.
This section has moved here: https://facebook.github.io/create-react-app/docs/code-splitting
This section has moved here: https://facebook.github.io/create-react-app/docs/analyzing-the-bundle-size
This section has moved here: https://facebook.github.io/create-react-app/docs/making-a-progressive-web-app
This section has moved here: https://facebook.github.io/create-react-app/docs/advanced-configuration
This section has moved here: https://facebook.github.io/create-react-app/docs/deployment
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