script: Dorny path filter generator (derived from deps of the provided package)

dorny-filters-generator.ts

import path from 'path'

// 1. Define root of project from which to resolve all packages
const ROOT = path.resolve(__dirname, '..')

// 2. Define the relative path of the package that we generate the dorny filters for
const PACK = process.argv[2]
if (PACK == null) {
  throw new Error(
    'Need to supply relative path argument for package you want to render dorny filter for'
  )
}
const PACKAGE_PATH = path.join(ROOT, PACK)

// NOTE: adapt the below to your project
const TASK = 'build-test-lint'
const LOCAL_PREFIX = '@my-platform/'

// 3. Read the package and derive Job labels from its name
const pack = require(`${PACKAGE_PATH}/package.json`)

const jobLabel = pack.name.replace(LOCAL_PREFIX, '').replace(/-/g, '_')
const changesJobLabel = `${jobLabel}_changes`
const taskJobLabel = `${jobLabel}_${TASK}`

// 4. Extract local deps and sort them and resolve their relative path
const deps = Object.keys(pack.dependencies ?? {}).filter((dep) =>
  dep.startsWith(LOCAL_PREFIX)
)
const devDeps = Object.keys(pack.devDependencies ?? {}).filter((dep) =>
  dep.startsWith(LOCAL_PREFIX)
)

const allDeps = [...deps, ...devDeps]
allDeps.sort()
allDeps.unshift(pack.name)

const resolvedDeps = allDeps.map((dep) => {
  const label = dep.replace(LOCAL_PREFIX, '').replace(/-/g, '_')
  return { label, relPath: path.relative(ROOT, require.resolve(dep)) }
})

// 5. Render functions for the different section pieces
function dornyOutput({ label }: { label: string }, indent: string) {
  return `${indent}${label}: \${{ steps.filter.outputs.${label} }}`
}

function dornyFilter(
  { label, relPath }: { label: string; relPath: string },
  indent: string = '          '
) {
  // Simplest (naive) way to find package root (one above first `/src`)
  // A more sophisticated way, i.e. finding `package.json` could be used
  const idxOfSrc = relPath.indexOf('/src')
  const packageRoot = relPath.slice(0, idxOfSrc)
  return `${indent}${label}:\n` + `${indent}  - './${packageRoot}/**'`
}

function dornyNeeds({ label }: { label: string }, indent: string) {
  return `${indent}needs.${changesJobLabel}.outputs.${label} == 'true'`
}

const packOutputs = resolvedDeps.map((x) => dornyOutput(x, '      ')).join('\n')
const packFilters = resolvedDeps
  .map((x) => dornyFilter(x, '            '))
  .join('\n')
const taskNeeds = resolvedDeps.map((x) => dornyNeeds(x, '      ')).join(' ||\n')

// 6. Piece it all together
const changesJob = `
jobs:
  ${changesJobLabel}:
    runs-on:
      group: Default
    outputs:
${packOutputs}
      action: \${{ steps.filter.outputs.action }}
      workflow: \${{ steps.filter.outputs.workflow }}

    steps:
      - uses: actions/checkout@master
        if: github.event_name != 'pull_request'

      - uses: dorny/paths-filter@v2
        id: filter
        with:
          filters: |
${packFilters}
            workflow:
              - '.github/workflows/${jobLabel}.yml'
            action:
              - '.github/actions/build-test-lint/action.yml'

  ${taskJobLabel}:
    needs: ${changesJobLabel}
    if: \${{
${taskNeeds} ||
      needs.account_runtime_changes.outputs.action == 'true'  ||
      needs.account_runtime_changes.outputs.workflow == 'true'
      }}
`

console.log(changesJob)