# Why can't I run "Hello World" react app similar to simplest html, css and js project?

**URL:** <https://forum.freecodecamp.org/t/why-cant-i-run-hello-world-react-app-similar-to-simplest-html-css-and-js-project/415713>\
**Category:** General\
**Created:** [August 17, 2020, 7:35am UTC](https://forum.freecodecamp.org/t/why-cant-i-run-hello-world-react-app-similar-to-simplest-html-css-and-js-project/415713 "2020-08-17T07:35:34Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![vikramvi](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/vikramvi/32/111118_2.png) [@vikramvi](https://forum.freecodecamp.org/u/vikramvi)\
**Post date:** [August 17, 2020, 7:35am UTC](https://forum.freecodecamp.org/t/why-cant-i-run-hello-world-react-app-similar-to-simplest-html-css-and-js-project/415713/1 "2020-08-17T07:35:34Z")

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Dear All,

After learning HTML, CSS and JS; I’ve started learning React and I’ve got this very basic query for which I couldn’t answer

1. I could just 3 files in `VSCode namely index.html, style.css and index.js`, later load `index.html` in browser to see the results

2. Why can’t I do same thing with React Code ?  
For writing simplest hello world program; I had to run `npx create-react-app helloworld` & do changes.  
Later run command npm start

3. If I do any code change, I need to stop and again run npm start

Questions:

1. Why do I need to run `npx create-react-app helloworld`

2. How to see new changes without stopping and re-running npm start ?

Thanks,  
Vikram

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**Author:** ![miku86](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/miku86/32/95580_2.png) [@miku86](https://forum.freecodecamp.org/u/miku86)\
**Post date:** [August 17, 2020, 8:32am UTC](https://forum.freecodecamp.org/t/why-cant-i-run-hello-world-react-app-similar-to-simplest-html-css-and-js-project/415713/2 "2020-08-17T08:32:55Z")

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> [@vikramvi](#):
>
> Why can’t I do same thing with React Code ?  
> For writing simplest hello world program; I had to run `npx create-react-app helloworld` & do changes.  
> Later run command npm start

You don’t have to do this.

The ReactJS Docs will guide you:

> **[Add React to an Existing Project – React](https://react.dev/learn/add-react-to-an-existing-project)**
>
> The library for web and native user interfaces

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> [@vikramvi](#):
>
> Why do I need to run `npx create-react-app helloworld`

Here you can read about the advantages of this:

> **[Start a New React Project – React](https://react.dev/learn/start-a-new-react-project)**
>
> The library for web and native user interfaces

* * *

> [@vikramvi](#):
>
> How to see new changes without stopping and re-running npm start ?

Normally, you don’t have to re-run `npm start`.

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**Author:** ![vikramvi](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/vikramvi/32/111118_2.png) [@vikramvi](https://forum.freecodecamp.org/u/vikramvi)\
**Post date:** [August 20, 2020, 5:49am UTC](https://forum.freecodecamp.org/t/why-cant-i-run-hello-world-react-app-similar-to-simplest-html-css-and-js-project/415713/3 "2020-08-20T05:49:47Z")

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Thanks for info, let me re-try steps you have mentioned

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**Author:** ![ILM](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/ilm/32/363239_2.png) [@ILM](https://forum.freecodecamp.org/u/ILM)\
**Post date:** [June 1, 2021, 6:43pm UTC](https://forum.freecodecamp.org/t/why-cant-i-run-hello-world-react-app-similar-to-simplest-html-css-and-js-project/415713/4 "2021-06-01T18:43:11Z")

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Closed on June 1, 2021, 6:43pm UTC