Getting Started Flashcards
How can I make react render in an element in the HTML?
By simply calling ReactDOM.Render(
,
document.getElementById(“existing-elem-on-html”)
)
Why can I write HTML in a javascript file and it does not throw an error?
Because this is not HTML but JSX. Doesn’t throw an error because the react lib is imported in the javascript file.
What happens when you create a react component that is called starting with a lower case letter?
It will try to render the html directly (eg: function button…). Components needs to start with CAPITAL letter
How is a react hook declared?
by creating an array with a getter and one setter which receive an useState() method e.g
const [counter, setCounter] = userState();
What does use state method returns?
an array containing two elements which are destructured into an array.
How to inititalize the value of the getter part of the array?
By passing an argument to the useState(0);
What the onClick event expects to receive? Does it need to be in curly braces?
It expects to receive a POINTER to a method, NOT the execution of the method. Necessary to be within curly braces.. e.g:
… onClick={myFunc}… AND NOT myFunc()
Can I assign arrow functions to events such as onClick?
Yes… e.g:
onClick={() => console.log(‘hello’)}
In a summarized way: what is React Hooks?
It hooks a simple component into a state.
How to update the getter part of the array? Do we need to declare it?
By calling setState(). No need to declare it.
What is a React.Fragment? What is the shortcut to react fragment?
It is a way to group components together and avoid using divs. The shortcut for it is using empty tags <>
What does the props variable contains?
Key value pairs
What is the common saying about props and state?
immutable props, mutable state
Should we use loops and whiles in react? Is it a hard requirement?
No, we have to make it declarative by using map/filter/reduce. Not a hard requirement.
What is a good UI candidate to turn into a component?
Items that share data OR behavior
