index.js

const core = require('@actions/core')
const github = require('@actions/github')
const match = require('./match.js')

function run() {
  try {
    const pr = github.context.payload.pull_request || {}
    const labels = pr.labels || []
    const labelNames = labels.map((label) => label.name)
    const allowedLabels = match.parseAllowed(core.getInput('allowed'))
    const allowedMultipleLabels = match.parseAllowed(
      core.getInput('allowed_multiple')
    )
    const defaultMatch = core.getInput('default_match')
    let matchingLabel
    if (allowedLabels.length > 0) {
      matchingLabel = match.findMatching(
        labelNames,
        allowedLabels,
        false,
        defaultMatch
      )
    } else if (allowedMultipleLabels.length > 0) {
      matchingLabel = match.findMatching(
        labelNames,
        allowedMultipleLabels,
        true,
        defaultMatch
      )
    } else {
      return core.setFailed(
        'You must provide either `allowed` or `allowed_multiple` as input.'
      )
    }

    core.setOutput('match', matchingLabel.join(', '))
  } catch (error) {
    core.setFailed(error.message)
  }
}

run()