Hello.
I’m following a tutorial on YouTube to get started with ReactJS. I’ve downloaded the starter template from reactjs.org I just want to see my first "Hello World! on the screen. But I fail.
I have an index.html file.
And I have the app.js file.
Please, check screenshots below.
Why it doesn’t work? I reviewed several times my tutorial. I don’t understand what is wrong with my code.
Could you please help. Can’t wait to get start and to move further 
Thank you very much in advance.
Helena
Hi @Helena_G! Welcome to the forums 
When you preview your page in your browser, do you see any errors in the Console in your browser developer tools?
Really strange! Can you copy/paste your code here? You can use this button to format your code correctly as part of the response:
From the screenshots, what you have should work.
class App extends React.Component() {
should be
class App extends React.Component {
There should be no parens in the extends clause (you can but just not in this case).
Thank you @senocular It did work Now, I can move on to the next tutorial.
Thank you @kirupa
Just curious, what drives your intuition about parentheses in cases like this?
The extends clause accepts any expression. So you can put just about anything there, including a function (invoked with parens) that you can call and return a class with.
class Animal {}
class FeralAnimal {}
function getAnimal () {
return Math.random() < 0.5 ? Animal : FeralAnimal;
}
class Cat extends getAnimal() {}
let missPrincess = new Cat();
console.log(missPrincess instanceof FeralAnimal); // ???
This is used with class-based mixins.
Ah right, this is JavaScript:
class A extends class B extends function(){ return function(){
return "senocular".constructor
}() }() { } { }
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