This action detects pre-release NPM packages for a given package file. Pre-release packages are often Alpha packages only to be used when developing however avoided when running production code. 

Required The full path pointing to the package file. Example "./package.json".

Boolean indicator used to tell that a pre-release packages was found.

jobs:
    precheck:
        runs-on: ubuntu-latest
        steps:
            - uses: kevin-bronsdijk/npm-pre-release-packages-detection-action@v1.0.0
              id: npmprerelease
              with:
                  package-file-full-path: './package.json'
            - run: echo "result ${{ steps.npmprerelease.outputs.found-pre-release }}"

Feel free to open an issue on this GitHub project.