yarn a simple demo

1. Create a new folder

mkdir ~/test

2. cd into the working directory

cd ~/test

3. Create a package.json 

vi ~/test/package.json

4. Add the following code 

{
"private":true,
"workspaces": ["client", "server"]
}

5. Next create two folders within the test folder called client & server these will represent our own packages

mkdir ~/test/client

mkdir ~/test/server

6.  Run yarn init within each folder and hit enter to initialize with all of the defaults

~/test/client yarn init

~/test/server yarn init

7. So now we have two projects client and server. We want to make one dependent on the other.

8. Within the server folder create a new file called server.js and add the following code

module.exports = () => {
console.log('hello from console');
}

9. Next create a new file within the client folder called client.js and add the following code

const commonFunction = require("common");
commonFunction();

10. To tell the client that the server exists we add dependency in the package.json in the client folder like below

"dependencies": {
"server": "1.0.0"
}

11. Next we run yarn install within the client folder to install dependencies

12 And if we go back to the root folder a new folder has been created called node_module

13. Next if we run client/client.js we should see the output and if we change server.js the output for the client will also change. This proves that the two folders have been symlinked.