DEV Community

Advanced Usage of Styled Components for your React App - Part 1

Olena Drugalya on February 15, 2021

In my previous post about styled components I wrote about the general features of Styled Components, how to set up and use them and why to use them...

Read full post

Orkhan Jafarov • Feb 15 '21

Nice explanation!
I'll add, in the new version of styled-components it possible to handle error when React throwing an error when you use unsupported/uncommon attributes for elements. styled-components.com/docs/api#tra...

Let's say:

<MenuNavigation opened  />
// Warning: unknown props 'opened' and bla bla

To handle it you can use $ symbol

<MenuNavigation $opened  />

const MenuNavigation = styled.div`
  display: ${props => props.$opened ? 'block' : 'none'};
`;

Sandeep18072002 • Feb 18 '21

Can you help why it is resulting in 10 ;

var i = 4;

for(var i = 0 ; i<10;i++){ // using var i for block scoping
console.log(i)
}

console.log(i) // consoling global 'i' but instead of 4 result get to +1 for the for
loop conditional { 10 };

why is it so ?? Please clear my doubt.... 🤔

Olena Drugalya • Feb 18 '21

its because you re-defined var i in your loop again, so the loop uses var i = 0. If you want var i to start from 4, you should do the following:
for(var i = 4 ; i<10;i++)
OR
for(var i = i ; i<10;i++)

Sandeep18072002 • Feb 18 '21

Bro I don't want to start my var from 4 I am saying that if-

var i = 4; // stored in globals

for(var i = 0; i<10; i++){
console.log(i); // the var is block scoped and and it's 0 it will iterate until i<10 which is just obvious but after the loop / The second console.log(i) ; refers to globals but it gives 10 ; instead of 4 or 9+4 = 13 ;; CONCERN is - why 10 [from where is became 10]
}
console.log(i); // 10 ??????????

Siva Prasad • Feb 20 '21

var doesn't create a block scope for the loop, it just rewrites the value for the variable i. Since the value of i changes to 10 after the loop ends, that will be printed. If you want to create a block scope for the loop, use let.

Lucas Perez • Feb 16 '21 • Edited

Nice article! Styled components are very cool, indeed.
What do you think about defining your styled components inside the same file as your normal component? This way you could potentially have a single file component, something that Vuers seem to love.
I haven't thought much about this much, just asking for some opinion.

Olena Drugalya • Feb 17 '21

Yes, you can surely do that. But it’s always good to devide logic from styling in my opinion. And sometimes a component can have only styles (like a wrapper), so it is not necessary to create separate file for that. Like you can have Menu.js and Menu.styles.js which include MenuWrapper and MenuContainer