const AWS = require('aws-sdk')

AWS.config.region = 'us-east-1'

// Functions
const getCredentials = IdentityId => {
  const cognito = new AWS.CognitoIdentity({ apiVersion: '2014-06-30' })
  const params = {
    IdentityId
  }
  return cognito.getCredentialsForIdentity(params).promise()
}

getCredentials('...')
  .then(data => {
    console.log(JSON.stringify(data, null, 2))
  })
  .catch(err => {
    console.log(err)
  })