How to open browser to localhost through npm scripts

Question

I've been trying to figure out how to write a npm script that will culminate with the application being launched in the user's browser without them having to manually open the browser and go to localhost:1234.

Right now my script reads as:

"start": "npm run build && npm run dev",
"build": "npm run clean && npm run mkdir && npm run build:html && npm run build:css && npm run build:js",
"dev": "webpack-dev-server --inline --hot --content-base build --history-api-fallback",

Wanting to add "open": <some code here>,

So when someone goes to GitHub and clones or forks off my repository they are given the instructions for how to run the application. I just thought that automating this would be a nice little addition.

Anyone know how this is possible? I'm pretty sure it is and think it has something to do with calling a command in bash. Thanks in advance for the help!

Answer 1

This can be achieved by including a couple of additional packages in your project.

Additional packages

Install http-server:

$ npm install http-server --save-dev

and concurrently:

$ npm install concurrently --save-dev

npm scripts

Add the following open script to package.json:

"scripts": {
    "start": "npm run open",
    "open": "concurrently \"http-server -a localhost -p 1234\" \"open http://localhost:1234/build\""
 }

Note

1. start will actually be defined as follows to include the tasks you currently have:

   "start": "npm run build && npm run dev && npm run open",
   

2. The code in the open script above which reads:

   open http://localhost:1234/build
   

   ...assumes that the build task you have previously defined outputs a index.html to a build folder. If the file is named differently you will need to define it. E.g.

   open http://localhost:1234/build/the_html_file_name.html
   

3. You may need to add a delay between launching the server and opening the file, just to wait a bit til the server starts up. If that's the case then also install sleep-ms:

   $ npm install sleep-ms --save-dev
   

   and change the open script to:

   "open": "concurrently \"http-server -a localhost -p 1234\" \"sleepms 1000 && open http://localhost:1234/build\""
   

Cross platform

Unfortunately, the open command is not supported cross-platform. To overcome this issue check out opener or opn-cli and replace the command accordingly.

However, both packages, (opener and opn-cli), utilize Object.assign() so will not run in older versions of nodejs.

Edit: To open a browser window after starting the server, http-server now accepts the -o option . This can be utilized instead of either the opener or opn-cli packages.