113 lines
2.6 KiB
Markdown
113 lines
2.6 KiB
Markdown
---
|
|
id: 5a24c314108439a4d403616c
|
|
title: Override Default Props
|
|
challengeType: 6
|
|
forumTopicId: 301399
|
|
dashedName: override-default-props
|
|
---
|
|
|
|
# --description--
|
|
|
|
The ability to set default props is a useful feature in React. The way to override the default props is to explicitly set the prop values for a component.
|
|
|
|
# --instructions--
|
|
|
|
The `ShoppingCart` component now renders a child component `Items`. This `Items` component has a default prop `quantity` set to the integer `0`. Override the default prop by passing in a value of `10` for `quantity`.
|
|
|
|
**Note:** Remember that the syntax to add a prop to a component looks similar to how you add HTML attributes. However, since the value for `quantity` is an integer, it won't go in quotes but it should be wrapped in curly braces. For example, `{100}`. This syntax tells JSX to interpret the value within the braces directly as JavaScript.
|
|
|
|
# --hints--
|
|
|
|
The component `ShoppingCart` should render.
|
|
|
|
```js
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(React.createElement(ShoppingCart));
|
|
return mockedComponent.find('ShoppingCart').length === 1;
|
|
})()
|
|
);
|
|
```
|
|
|
|
The component `Items` should render.
|
|
|
|
```js
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(React.createElement(ShoppingCart));
|
|
return mockedComponent.find('Items').length === 1;
|
|
})()
|
|
);
|
|
```
|
|
|
|
The `Items` component should have a prop of `{ quantity: 10 }` passed from the `ShoppingCart` component.
|
|
|
|
```js
|
|
(getUserInput) =>
|
|
assert(
|
|
(function () {
|
|
const mockedComponent = Enzyme.mount(React.createElement(ShoppingCart));
|
|
return (
|
|
mockedComponent.find('Items').props().quantity == 10 &&
|
|
getUserInput('index')
|
|
.replace(/ /g, '')
|
|
.includes('<Itemsquantity={10}/>')
|
|
);
|
|
})()
|
|
);
|
|
```
|
|
|
|
# --seed--
|
|
|
|
## --after-user-code--
|
|
|
|
```jsx
|
|
ReactDOM.render(<ShoppingCart />, document.getElementById('root'))
|
|
```
|
|
|
|
## --seed-contents--
|
|
|
|
```jsx
|
|
const Items = (props) => {
|
|
return <h1>Current Quantity of Items in Cart: {props.quantity}</h1>
|
|
}
|
|
|
|
Items.defaultProps = {
|
|
quantity: 0
|
|
}
|
|
|
|
class ShoppingCart extends React.Component {
|
|
constructor(props) {
|
|
super(props);
|
|
}
|
|
render() {
|
|
{ /* Change code below this line */ }
|
|
return <Items />
|
|
{ /* Change code above this line */ }
|
|
}
|
|
};
|
|
```
|
|
|
|
# --solutions--
|
|
|
|
```jsx
|
|
const Items = (props) => {
|
|
return <h1>Current Quantity of Items in Cart: {props.quantity}</h1>
|
|
}
|
|
|
|
Items.defaultProps = {
|
|
quantity: 0
|
|
}
|
|
|
|
class ShoppingCart extends React.Component {
|
|
constructor(props) {
|
|
super(props);
|
|
}
|
|
render() {
|
|
{ /* Change code below this line */ }
|
|
return <Items quantity = {10} />
|
|
{ /* Change code above this line */ }
|
|
}
|
|
};
|
|
```
|