How to use the cozy-client-js.Client function in cozy-client-js

return new Promise((resolve, reject) => {
    try {
      // try to load a locally stored token and use that
      log.debug('Using token file ' + tokenPath)
      let stored = require(tokenPath)
      let cozyClient = new cozy.Client()

      cozyClient.init({
        cozyURL: url,
        token: stored.token
      })

      resolve(cozyClient)
    } catch (err) {
      reject(err)
    }
  })
}

exported.getClientWithoutToken = tokenPath => (url, docTypes = []) => {
  let permissions = docTypes.map(docType => docType.toString() + ':ALL')

  // Needed for ACH revocation after execution
  permissions.push('io.cozy.oauth.clients:ALL')

  let cozyClient = new cozy.Client({
    cozyURL: url,
    oauth: {
      storage: new cozy.MemoryStorage(),
      clientParams: {
        redirectURI: 'http://localhost:3333/do_access',
        softwareID: SOFTWARE_ID,
        clientName: CLIENT_NAME,
        scopes: permissions
      },
      onRegistered: onRegistered
    }
  })

  return cozyClient.authorize().then(creds => {
    let token = creds.token.accessToken
    cozyClient._token = new AppToken({ token })

exported.getClientWithTokenString = tokenString => async url => {
  const client = new cozy.Client()
  client.init({ cozyURL: url, token: tokenString })
  return client
}