docs/script/deployment/create-app.js

#!/usr/bin/env node
import Heroku from 'heroku-client'
import createAppName from './create-staging-app-name.js'

export default async function createApp(pullRequest) {
  // Extract some important properties from the PR
  const {
    number: pullNumber,
    base: {
      repo: { name: repo },
    },
    head: { ref: branch },
  } = pullRequest

  const appName = createAppName({ prefix: 'ghd', repo, pullNumber, branch })

  // Check if there's already a Heroku App for this PR, if not create one
  let appExists = true
  const heroku = new Heroku({ token: process.env.HEROKU_API_TOKEN })

  try {
    await heroku.get(`/apps/${appName}`)
  } catch (e) {
    appExists = false
  }

  if (!appExists) {
    try {
      const newApp = await heroku.post('/apps', {
        body: {
          name: appName,
        },
      })

      console.log('Heroku App created', newApp)
    } catch (error) {
      throw new Error(`Failed to create Heroku App ${appName}. Error: ${error}`)
    }
  } else {
    console.log(`Heroku App ${appName} already exists.`)
  }

  return appName
}