netlify-cli/src/detectors/docusaurus.js

const { hasRequiredDeps, hasRequiredFiles, getYarnOrNPMCommand, scanScripts } = require('./utils/jsdetect')
module.exports = function() {
  // REQUIRED FILES
  if (!hasRequiredFiles(['package.json', 'siteConfig.js'])) return false
  // REQUIRED DEPS
  if (!hasRequiredDeps(['docusaurus'])) return false

  /** everything below now assumes that we are within gatsby */

  const possibleArgsArrs = scanScripts({
    preferredScriptsArr: ['start'],
    preferredCommand: 'docusaurus-start'
  })

  return {
    type: 'docusaurus',
    command: getYarnOrNPMCommand(),
    port: 8888,
    proxyPort: 3000,
    env: { ...process.env },
    possibleArgsArrs,
    urlRegexp: new RegExp(`(http://)([^:]+:)${3000}(/)?`, 'g'),
    dist: 'static'
  }
}