index.js

async function publishItem (instanceZUID, modelZUID, itemZUID, version) {
  const options = {
    method: 'POST',
    hostname: `${instanceZUID}.api.zesty.io`,
    path: `/v1/content/models/${modelZUID}/items/${itemZUID}/publishings`,
    headers: {
      'Content-Type': 'application/json',
      Authorization: `Bearer ${DEV_TOKEN}`
    }
  }

  const req = https.request(options, function (res) {
    const chunks = []

    res.on('data', function (chunk) {
      chunks.push(chunk)
    })

    res.on('end', function (chunk) {
      const body = Buffer.concat(chunks)
      console.log(body.toString())
    })

    res.on('error', function (error) {
      console.error(error)
    })
  })

  const postData = {
    version: version,
    publishAt: 'now',
    unpublishAt: '2019-12-31'
  }
  req.write(JSON.stringify(postData))
  req.end()
}