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gotchajavascriptreactCritical

Difference between npx and npm?

Submitted by: @import:stackoverflow-api··
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npxandbetweennpmdifference

Problem

I have just started learning React, and Facebook helps in simplifying the initial setup by providing the following ready-made project.

If I have to install the skeleton project I have to type npx create-react-app my-app in command-line.

I was wondering why does the Facebook in Github have npx create-react-app my-app rather than npm create-react-app my-app?

Solution

Introducing npx: an npm package runner
NPM - Manages packages but doesn't make life easy executing any.
NPX - A tool for executing Node packages.

NPX comes bundled with NPM version 5.2+

NPM by itself does not simply run any package. It doesn't run any package as a matter of fact. If you want to run a package using NPM, you must specify that package in your package.json file.

When executables are installed via NPM packages, NPM links to them:

  • local installs have "links" created at ./node_modules/.bin/ directory.



  • global installs have "links" created from the global bin/ directory (e.g. /usr/local/bin) on Linux or at %AppData%/npm on Windows.



Documentation you should read

NPM:

One might install a package locally on a certain project:

npm install some-package


Now let's say you want NodeJS to execute that package from the command line:

$ some-package


The above will fail. Only globally installed packages can be executed by typing their name only.

To fix this, and have it run, you must type the local path:

$ ./node_modules/.bin/some-package


You can technically run a locally installed package by editing your packages.json file and adding that package in the scripts section:

{
  "name": "whatever",
  "version": "1.0.0",
  "scripts": {
    "some-package": "some-package"
  }
}


Then run the script using npm run-script (or npm run):

npm run some-package


NPX:

npx will check whether ` exists in $PATH, or in the local project binaries, and execute it. So, for the above example, if you wish to execute the locally-installed package some-package all you need to do is type:

npx some-package


Another major advantage of
npx is the ability to execute a package which wasn't previously installed:

$ npx create-react-app my-app


The above example will generate a
react app boilerplate within the path the command had run in, and ensures that you always use the latest version of a generator or build tool without having to upgrade each time you’re about to use it.

Use-Case Example:

npx command may be helpful in the script section of a package.json file,
when it is unwanted to define a dependency which might not be commonly used or any other reason:
"scripts": {
"start": "npx gulp@3.9.1",
"serve": "npx http-server"
}


Call with:
npm run serve`

Related questions:

  • How to use package installed locally in node_modules?



  • NPM: how to source ./node_modules/.bin folder?



  • How do you run a js file using npm scripts?

Code Snippets

npm install some-package
$ some-package
$ ./node_modules/.bin/some-package
{
  "name": "whatever",
  "version": "1.0.0",
  "scripts": {
    "some-package": "some-package"
  }
}
npm run some-package

Context

Stack Overflow Q#50605219, score: 1278

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