In previous posts we’ve used Github actions to build .NET core code, now let’s create a workflow to build/transpile a TypeScript application.

• Create a file (mine’s named build.yml) in your Github repo. in the folder .github/workflows
• As per other examples of such a .yml action file we need to give the build a name and set up the triggers, so let’s do that, here’s the code

  name: Build
  
  on:
    push:
      branches: [ master ]
    pull_request:
      branches: [ master ]
  
  jobs:
    build:
  
      runs-on: ubuntu-latest
  

  In the above we’ve simply named the action Build which is triggered by pushes to master (and pull requests). We then set the action up to run on an ubuntu VM

• Next we’ll add the following code to create a strategy (basically think, job configurations and application wide variables)

  strategy:
    matrix:
      node-version: [12.x]
  

  In this case we’re creating a variable named node-version with the version of node we want to use.

• Now we’ll create the steps for the build

  steps:
    - uses: actions/checkout@v2
    - name: Node.js
      uses: actions/setup-node@v1
      with:
        node-version: ${{ matrix.node-version }}
    - run: npm install -g yarn    
    - name: yarn install, build and test
      run: | 
        yarn 
        yarn build
        yarn test
  

  Firstly we declare the checkout action to be used, then we used the setup-node action to (as the name suggests) setup node with the version we defined. In this example we then run npm to install yarn. Obviously we could have simply used npm instead (and you can replace the yarn commands with npm if you wish).

  Finally we have a step to install, build and test our code running the relevant yarn commands to carry out these tasks.

The above expects the package.json of your project to have scripts named test and build. For example

"scripts": {
  "test": "jest",
  "build": "tsc"
}