auth0-delegate.html

<link rel="import" href="../polymer/polymer-element.html">
<link rel="import" href="auth0.html">

<dom-module id="auth0-delegate">

  <template>
  </template>

  <script>
    class Auth0Delegate extends Polymer.Element {
      static get is() { return 'auth0-delegate'; }
      static get properties() {
        return {
          idToken: {
            type: String
          },
          options: {
            type: Object
          },
          clientId: {
            type: String
          },
          domain: {
            type: String
          },
          delegateToken: {
            type: String,
            readOnly: true,
            notify: true,
            value: ''
          }
        }
      }
      static get observers() {
        return [
          '_getDelegateToken(domain, clientId, idToken, options)'
        ]
      }

      _getDelegateToken(domain, clientId, idToken, options) {
        if(clientId !== undefined && domain !== undefined && options !== undefined && idToken !== undefined) {
          var auth = new auth0.Authentication({
            domain:       this.domain,
            clientID:     this.clientId
          });
          var options = {
            id_token: this.idToken,
            apiType: this.options.api,
            scope: this.options.scope,
            target: this.clientId,
            grant_type: 'urn:ietf:params:oauth:grant-type:jwt-bearer'
          };
          // Make a call to the Auth0 '/delegate'
          auth.delegation(options, function(err, result) {
            if(!err) {
              this._setDelegateToken(result.idToken);
            }
          }.bind(this));
        }
      }
    }

    customElements.define(Auth0Delegate.is, Auth0Delegate);
  </script>
</dom-module>