Files
Shaun Hamilton c2a11ad00d feat: add 'back/front end' in curriculum (#42596)
* 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>
2021-08-13 21:57:13 -05:00

147 lines
4.2 KiB
Markdown

---
id: 5a24c314108439a4d4036177
title: Scrivere un semplice contatore
challengeType: 6
forumTopicId: 301425
dashedName: write-a-simple-counter
---
# --description--
È possibile progettare un componente stateful più complesso combinando i concetti visti finora. Questi includono l'inizializzazione dello `state`, la scrittura di metodi che impostano lo `state` e l'assegnazione di gestori di click per attivare questi metodi.
# --instructions--
Il componente `Counter` tiene traccia di un valore `count` nello `state`. Ci sono due bottoni che chiamano i metodi `increment()` e `decrement()`. Scrivi questi metodi in modo che il valore del contatore venga incrementato o decrementato di 1 quando viene fatto click sul bottone appropriato. Inoltre, crea un metodo `reset()` in modo che quando si clicca il pulsante reset, il conteggio venga impostato a 0.
**Nota:** Assicurati di non modificare le `className` dei bottoni. Inoltre, ricordati di aggiungere i legami (bindings) necessari ai metodi appena creati nel costruttore.
# --hints--
`Counter` dovrebbe restituire un elemento `div` che contiene tre pulsanti con contenuto di testo nell'ordine: `Increment!`, `Decrement!`, `Reset`.
```js
assert(
(() => {
const mockedComponent = Enzyme.mount(React.createElement(Counter));
return (
mockedComponent.find('.inc').text() === 'Increment!' &&
mockedComponent.find('.dec').text() === 'Decrement!' &&
mockedComponent.find('.reset').text() === 'Reset'
);
})()
);
```
Lo stato di `Counter` dovrebbe essere inizializzato con una proprietà `count` impostata a `0`.
```js
const mockedComponent = Enzyme.mount(React.createElement(Counter));
assert(mockedComponent.find('h1').text() === 'Current Count: 0');
```
Cliccando sul bottone di incremento il conteggio dovrebbe aumentare di `1`.
```js
const mockedComponent = Enzyme.mount(React.createElement(Counter));
mockedComponent.find('.inc').simulate('click');
assert(mockedComponent.find('h1').text() === 'Current Count: 1');
```
Cliccando sul bottone di decremento il conteggio dovrebbe diminuire di `1`.
```js
const mockedComponent = Enzyme.mount(React.createElement(Counter));
mockedComponent.find('.dec').simulate('click');
assert(mockedComponent.find('h1').text() === 'Current Count: -1');
```
Cliccando sul bottone di reset il conteggio dovrebbe essere reimpostato a `0`.
```js
const mockedComponent = Enzyme.mount(React.createElement(Counter));
mockedComponent.setState({ count: 5 });
const currentCountElement = mockedComponent.find('h1');
assert(currentCountElement.text() === 'Current Count: 5');
mockedComponent.find('.reset').simulate('click');
assert(currentCountElement.text() === 'Current Count: 0');
```
# --seed--
## --after-user-code--
```jsx
ReactDOM.render(<Counter />, document.getElementById('root'))
```
## --seed-contents--
```jsx
class Counter extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0
};
// Change code below this line
// Change code above this line
}
// Change code below this line
// Change code above this line
render() {
return (
<div>
<button className='inc' onClick={this.increment}>Increment!</button>
<button className='dec' onClick={this.decrement}>Decrement!</button>
<button className='reset' onClick={this.reset}>Reset</button>
<h1>Current Count: {this.state.count}</h1>
</div>
);
}
};
```
# --solutions--
```jsx
class Counter extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0
};
this.increment = this.increment.bind(this);
this.decrement = this.decrement.bind(this);
this.reset = this.reset.bind(this);
}
reset() {
this.setState({
count: 0
});
}
increment() {
this.setState(state => ({
count: state.count + 1
}));
}
decrement() {
this.setState(state => ({
count: state.count - 1
}));
}
render() {
return (
<div>
<button className='inc' onClick={this.increment}>Increment!</button>
<button className='dec' onClick={this.decrement}>Decrement!</button>
<button className='reset' onClick={this.reset}>Reset</button>
<h1>Current Count: {this.state.count}</h1>
</div>
);
}
};
```