Inside map function why is the function defined with ( ) => ( ) instead of ( ) => { }
{mylist.map((elem, index) => (
<div key={elem.id}>
<h2>{elem.title}</h2>
</div>
))}
You can leave () out if you put everything in one line:
{mylist.map((elem, index) => <div key={elem.id}><h2>{elem.title}</h2></div>)}
If you want to return something, but it take several lines, then you have to use ():
{mylist.map((elem, index) => (
<div key={elem.id}>
<h2>{elem.title}</h2>
</div>
))}
Finally, when you want to perform something and THEN return the result, you need to use {}. You still need to care when you return something - if it takes several lines, you have to wrap it with():
{mylist.map((elem, index) => {
const id = elem.id;
const title = elem.title;
return (
<div key={id}>
<h2>{title}</h2>
</div>
);
})}
For returning objects it's also a bit different: You can wrap your object into brackets: ({...}) or explicitly return it: () => { return { ... }}