* chore: rename APIs and Microservices to include "Backend" (#42515) * fix typo * fix typo * undo change * Corrected grammar mistake Corrected a grammar mistake by removing a comma. * change APIs and Microservices cert title * update title * Change APIs and Microservices certi title * Update translations.json * update title * feat(curriculum): rename apis and microservices cert * rename folder structure * rename certificate * rename learn Markdown * apis-and-microservices -> back-end-development-and-apis * update backend meta * update i18n langs and cypress test Co-authored-by: Shaun Hamilton <shauhami020@gmail.com> * fix: add development to front-end libraries (#42512) * fix: added-the-word-Development-to-front-end-libraries * fix/added-the-word-Development-to-front-end-libraries * fix/added-word-development-to-front-end-libraries-in-other-related-files * fix/added-the-word-Development-to-front-end-and-all-related-files * fix/removed-typos-from-last-commit-in-index.md * fix/reverted-changes-that-i-made-to-dependecies * fix/removed xvfg * fix/reverted changes that i made to package.json * remove unwanted changes * front-end-development-libraries changes * rename backend certSlug and README * update i18n folder names and keys * test: add legacy path redirect tests This uses serve.json from the client-config repo, since we currently use that in production * fix: create public dir before moving serve.json * fix: add missing script * refactor: collect redirect tests * test: convert to cy.location for stricter tests * rename certificate folder to 00-certificates * change crowdin config to recognise new certificates location * allow translations to be used Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com> * add forwards slashes to path redirects * fix cypress path tests again * plese cypress * fix: test different challenge Okay so I literally have no idea why this one particular challenge fails in Cypress Firefox ONLY. Tom and I paired and spun a full build instance and confirmed in Firefox the page loads and redirects as expected. Changing to another bootstrap challenge passes Cypress firefox locally. Absolutely boggled by this. AAAAAAAAAAAAAAA * fix: separate the test Okay apparently the test does not work unless we separate it into a different `it` statement. >:( >:( >:( >:( Co-authored-by: Sujal Gupta <55016909+heysujal@users.noreply.github.com> Co-authored-by: Noor Fakhry <65724923+NoorFakhry@users.noreply.github.com> Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com> Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com>
135 lines
3.3 KiB
Markdown
135 lines
3.3 KiB
Markdown
---
|
|
id: 5a24c314108439a4d4036170
|
|
title: Create a Stateful Component
|
|
challengeType: 6
|
|
forumTopicId: 301391
|
|
dashedName: create-a-stateful-component
|
|
---
|
|
|
|
# --description--
|
|
|
|
One of the most important topics in React is `state`. State consists of any data your application needs to know about, that can change over time. You want your apps to respond to state changes and present an updated UI when necessary. React offers a nice solution for the state management of modern web applications.
|
|
|
|
You create state in a React component by declaring a `state` property on the component class in its `constructor`. This initializes the component with `state` when it is created. The `state` property must be set to a JavaScript `object`. Declaring it looks like this:
|
|
|
|
```jsx
|
|
this.state = {
|
|
|
|
}
|
|
```
|
|
|
|
You have access to the `state` object throughout the life of your component. You can update it, render it in your UI, and pass it as props to child components. The `state` object can be as complex or as simple as you need it to be. Note that you must create a class component by extending `React.Component` in order to create `state` like this.
|
|
|
|
# --instructions--
|
|
|
|
There is a component in the code editor that is trying to render a `name` property from its `state`. However, there is no `state` defined. Initialize the component with `state` in the `constructor` and assign your name to a property of `name`.
|
|
|
|
# --hints--
|
|
|
|
`StatefulComponent` should exist and render.
|
|
|
|
```js
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(
|
|
React.createElement(StatefulComponent)
|
|
);
|
|
return mockedComponent.find('StatefulComponent').length === 1;
|
|
})()
|
|
);
|
|
```
|
|
|
|
`StatefulComponent` should render a `div` and an `h1` element.
|
|
|
|
```js
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(
|
|
React.createElement(StatefulComponent)
|
|
);
|
|
return (
|
|
mockedComponent.find('div').length === 1 &&
|
|
mockedComponent.find('h1').length === 1
|
|
);
|
|
})()
|
|
);
|
|
```
|
|
|
|
The state of `StatefulComponent` should be initialized with a property `name` set to a string.
|
|
|
|
```js
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(
|
|
React.createElement(StatefulComponent)
|
|
);
|
|
const initialState = mockedComponent.state();
|
|
return (
|
|
typeof initialState === 'object' && typeof initialState.name === 'string'
|
|
);
|
|
})()
|
|
);
|
|
```
|
|
|
|
The property `name` in the state of `StatefulComponent` should render in the `h1` element.
|
|
|
|
```js
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(
|
|
React.createElement(StatefulComponent)
|
|
);
|
|
const initialState = mockedComponent.state();
|
|
return mockedComponent.find('h1').text() === initialState.name;
|
|
})()
|
|
);
|
|
```
|
|
|
|
# --seed--
|
|
|
|
## --after-user-code--
|
|
|
|
```jsx
|
|
ReactDOM.render(<StatefulComponent />, document.getElementById('root'))
|
|
```
|
|
|
|
## --seed-contents--
|
|
|
|
```jsx
|
|
class StatefulComponent extends React.Component {
|
|
constructor(props) {
|
|
super(props);
|
|
// Only change code below this line
|
|
|
|
// Only change code above this line
|
|
}
|
|
render() {
|
|
return (
|
|
<div>
|
|
<h1>{this.state.name}</h1>
|
|
</div>
|
|
);
|
|
}
|
|
};
|
|
```
|
|
|
|
# --solutions--
|
|
|
|
```jsx
|
|
class StatefulComponent extends React.Component {
|
|
constructor(props) {
|
|
super(props);
|
|
this.state = {
|
|
name: 'freeCodeCamp!'
|
|
}
|
|
}
|
|
render() {
|
|
return (
|
|
<div>
|
|
<h1>{this.state.name}</h1>
|
|
</div>
|
|
);
|
|
}
|
|
};
|
|
```
|