title: Do I need amazon-cognito-identity-js if I already have the aws-sdk (javascript)?
body: <p>I have a javascript project where I use the aws-sdk. No I want to use <a href="https://github.com/aws/amazon-cognito-identity-js" rel="nofollow noreferrer">amazon-cognito-identity-js</a>. On the page it says:</p>
  
  <blockquote>
    <p>Note that the Amazon Cognito AWS SDK for JavaScript is just a slimmed down version 
    of the AWS Javascript SDK namespaced as AWSCognito instead of AWS. It
    references only the Amazon Cognito Identity service.</p>
  </blockquote>
  
  <p>and indeed, I can for example create CognitoIdentityServiceProvider with:</p>
  
  <pre><code>CognitoIdentityServiceProvider = new AWS.CognitoIdentityServiceProvider();
  </code></pre>
  
  <p>But how do I do thinks like authenticate a user? According to the <a href="https://github.com/aws/amazon-cognito-identity-js" rel="nofollow noreferrer">amazon-cognito-identity-js</a> documentation:</p>
  
  <pre><code>authenticationDetails = new CognitoIdentityServiceProvider.AuthenticationDetails({Userame: ..., Password: ...});
  cognitoUser.authenticateUser(authenticationDetails, ...)
  </code></pre>
  
  <p>But the CognitoIdentityServiceProvider object does not have a AuthenticationDetails property.</p>
  
  <p>Do I have to do something different when I use the aws-sdk instead of amazon-cognito-identity-js?</p>
  
  <p>Or is my assumption wrong, and I need both, the aws-sdk and amazon-cognito-identity-js?</p>