A simple counter app using React
Liz Mahoney
For this assignment, you will be creating a simple counter application that uses this.setState and this.state to update and capture the state of a displayed counter each time that a button is clicked. For example, if the "+" button is clicked, the displayed counter will increment by 1. If the "-" button is clicked, the counter will decrement by 1.
Number and name of feature: Add Counter Feature
Estimate of time needed to complete: 1 hr
Start time: 9:00am
Finish time: 930am
Actual time needed to complete: 30 mins
Create the following components, all within your app.js file.
<App>
Should contain your <Counter>
component and should be wrapped in <React.Fragment>
. The component hierarchy should looks as follows:
<App>
<Counter>
<Counter>
Should contain the following state:
this.state = {
count: 0,
};
Should contain a
element that contains the current number of clicks against your counter. On initialization, it should start with/display "0". Should contain a button that displays a "+" for incrementing the counter. On click, the count property on your state should update/increment by 1 and the
element referenced above should display the result. Should contain a button that displays a "-" for decrementing the counter. On click, the count property on your state should update/decrement by 1 and the
element referenced above should display the result.
Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.
The page will reload if you make edits.
You will 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
This section has moved here: https://facebook.github.io/create-react-app/docs/troubleshooting#npm-run-build-fails-to-minify