how to run angular 4 app and nodejs api on same port 4200 for both production and development?

You can't have two different applications running on the same port. Angular-cli uses a nodejs server (technically it's webpack-dev-server) behind the scenes when you run ng serve, which means that port is already in use.

There are two possible solutions.

1. Use your node application to serve the static frontend files. Then you can't really use ng serve (this is probably what you'd do when running live).

2. Use nodejs with a different port, and use Angular's proxy config, to have Angular think the api port is actually 4200 (this is probably best during development).

This is primarily a concern during development I reckon, since you most likely wont (and shouldn't) be using ng serve live, so option 2 would be my best recommendation.

To configure a proxy, you create a file in your angular application root directory called proxy.config.json with the following content:

{
  "/api/*": {
    "target": "http://localhost:3000",
    "secure": false,
    "changeOrigin": true
  }
}

Then when you run ng serve, you run it with ng serve --proxy-config proxy.config.json instead.

Here's a link to the documentation

---

Here's an alternative when building for production (solution 1 above):

To build in production you use ng build --prod to create a production ready Angular build and then (assuming you use Express on your node server), use something like app.use(express.static('dist/')) as explained in the Express documentation. I'm not using node myself (I'm using .NET Core) so I'm afraid I can't provide much more in terms of details.

There is one awesome blog on medium by Daniel Kagan which explain all, here the link. Hot deploy its explain about client hot deployment i added some more code to make client and server hot deployment.

This answer is purely for development hot reload

Step one.

Install concurrently and nodemon

npm i concurrently

npm i nodemon

You can install globally as well with -g flag

Step Two.

Open your servers package.json file, and add following four line to it. Note i have my angular code inside client folder so i did cd client

"buildclient": "cd client && ng build",
"runclient": "cd client && npm start",
"devstart": "nodemon --inspect ./bin/www",
"dev": "npm run buildclient & concurrently --kill-others \"npm run runclient\" \"npm run devstart\""

If you don't want inspect node app then remove --inspect flag.

Step Three.

Go to your angular folder and create file proxy.conf.json add following line to file.

 {
   "/api/*": {
   "target": "http://localhost:3000",
   "secure": false,
   "changeOrigin": true
 }
 }

Step Four.

Add following command inside angular's package.json file

"start": "ng serve --proxy-config proxy.conf.json"

Step Five.

Make angular build output directory inside public folder of server. To do this go to angular.json change build outputPath to ../public following is JSON snippet.

"options": {
        "outputPath": "../public",
        "index": "src/index.html",
        "main": "src/main.ts",
        "polyfills": "src/polyfills.ts",
        "tsConfig": "src/tsconfig.app.json",
        "assets": [
          "src/favicon.ico",
          "src/assets"
        ],
        "styles": [
          "src/styles.css"
        ],
        "scripts": []
      },

Step Six.

Make sure your node express server app.js file read static files from public folder.

app.use(express.static(path.join(__dirname, 'public')));

Step Seven.

npm run dev

Done goto http://localhost:4200 you can see you app there :) all call to /api will get to node express server.

Any changes to server or client will be hot deployed automatically.

NOTE I used Express application generator to create my server and Angular CLI to create angular application. If you did it some other way then some files might not be present

1.first build you angular 6 app run ng build --watch

2.from nodejs app write this middle ware app.use(express.static(path.join(__dirname, './client/dist/client'))); as the folder pointing to client/dist/client is build folder of angular 6 app.

then run nodemon --inspect app.js

make sure to have a hirearchy of folders like this

/myproject /client /dist /client /.... /index.html /app.js /.....

listen to the port you want to run from app.js and run localhost:portno

hope this helps