gapi.load('client', () => {
  // now we can use gapi.client
  // ...
});

gapi.client.load('deploymentmanager', 'v2', () => {
  // now we can use gapi.client.deploymentmanager
  // ...
});

// declare client_id registered in Google Developers Console
var client_id = '',
  scope = [ 
      // See, edit, configure, and delete your Google Cloud data and see the email address for your Google Account.
      'https://www.googleapis.com/auth/cloud-platform',

      // View your data across Google Cloud services and see the email address of your Google Account
      'https://www.googleapis.com/auth/cloud-platform.read-only',

      // View and manage your Google Cloud Platform management resources and deployment status information
      'https://www.googleapis.com/auth/ndev.cloudman',

      // View your Google Cloud Platform management resources and deployment status information
      'https://www.googleapis.com/auth/ndev.cloudman.readonly',
    ],
    immediate = true;
// ...

gapi.auth.authorize(
  { client_id: client_id, scope: scope, immediate: immediate },
  authResult => {
    if (authResult && !authResult.error) {
        /* handle successful authorization */
    } else {
        /* handle authorization error */
    }
});

/*
Cancels and removes the preview currently associated with the deployment.
*/
await gapi.client.deploymentmanager.deployments.cancelPreview({ deployment: "deployment", project: "project",  });

/*
Deletes a deployment and all of the resources in the deployment.
*/
await gapi.client.deploymentmanager.deployments.delete({ deployment: "deployment", project: "project",  });

/*
Gets information about a specific deployment.
*/
await gapi.client.deploymentmanager.deployments.get({ deployment: "deployment", project: "project",  });

/*
Gets the access control policy for a resource. May be empty if no such policy or resource exists.
*/
await gapi.client.deploymentmanager.deployments.getIamPolicy({ project: "project", resource: "resource",  });

/*
Creates a deployment and all of the resources described by the deployment manifest.
*/
await gapi.client.deploymentmanager.deployments.insert({ project: "project",  });

/*
Lists all deployments for a given project.
*/
await gapi.client.deploymentmanager.deployments.list({ project: "project",  });

/*
Patches a deployment and all of the resources described by the deployment manifest.
*/
await gapi.client.deploymentmanager.deployments.patch({ deployment: "deployment", project: "project",  });

/*
Sets the access control policy on the specified resource. Replaces any existing policy.
*/
await gapi.client.deploymentmanager.deployments.setIamPolicy({ project: "project", resource: "resource",  });

/*
Stops an ongoing operation. This does not roll back any work that has already been completed, but prevents any new work from being started.
*/
await gapi.client.deploymentmanager.deployments.stop({ deployment: "deployment", project: "project",  });

/*
Returns permissions that a caller has on the specified resource.
*/
await gapi.client.deploymentmanager.deployments.testIamPermissions({ project: "project", resource: "resource",  });

/*
Updates a deployment and all of the resources described by the deployment manifest.
*/
await gapi.client.deploymentmanager.deployments.update({ deployment: "deployment", project: "project",  });

/*
Gets information about a specific manifest.
*/
await gapi.client.deploymentmanager.manifests.get({ deployment: "deployment", manifest: "manifest", project: "project",  });

/*
Lists all manifests for a given deployment.
*/
await gapi.client.deploymentmanager.manifests.list({ deployment: "deployment", project: "project",  });

/*
Gets information about a specific operation.
*/
await gapi.client.deploymentmanager.operations.get({ operation: "operation", project: "project",  });

/*
Lists all operations for a project.
*/
await gapi.client.deploymentmanager.operations.list({ project: "project",  });

/*
Gets information about a single resource.
*/
await gapi.client.deploymentmanager.resources.get({ deployment: "deployment", project: "project", resource: "resource",  });

/*
Lists all resources in a given deployment.
*/
await gapi.client.deploymentmanager.resources.list({ deployment: "deployment", project: "project",  });

/*
Lists all resource types for Deployment Manager.
*/
await gapi.client.deploymentmanager.types.list({ project: "project",  });