React Course first exercise

Hello guys,
Please i need help.
when I click on the delete button, on the first react exercise, all the categories are deleted instead only one.

contact me at → and we can learn together Andreson

That’s most probably because at the time Mosh recorded the tutorial the Javascript version for the Filter method didn’t require a return for the method, but now the best thing to do is:

handleDelete = (movie) => {
const movies = this.state.movies.filter((mov) => {
  return mov._id !== movie._id;
this.setState({ movies: movies });


Thanks Kodertian! It works.

Hi @Kodertian.

It isn’t due to differences in JavaScript versions. The actual reason is that when you put curly braces ({}) around the body, you need to explicitly write the return keyword, or otherwise it means that you aren’t returning anything.

Developer.mozilla explains it well (see Step 2.):

// Traditional Function
function (a){
  return a + 100;

// Arrow Function Break Down

// 1. Remove the word "function" and place arrow between the argument and opening body bracket
(a) => {
  return a + 100;

// 2. Remove the body brackets and word "return" -- the return is implied.
(a) => a + 100;

// 3. Remove the argument parentheses
a => a + 100;

@Andreson26 I hope you understand the issue now.

1 Like

Thanks man for the tip!