{"action":"opened","issue":{"url":"https://api.github.com/repos/EventStore/docs.geteventstore.com/issues/137","labels_url":"https://api.github.com/repos/EventStore/docs.geteventstore.com/issues/137/labels{/name}","comments_url":"https://api.github.com/repos/EventStore/docs.geteventstore.com/issues/137/comments","events_url":"https://api.github.com/repos/EventStore/docs.geteventstore.com/issues/137/events","html_url":"https://github.com/EventStore/docs.geteventstore.com/issues/137","id":109437032,"number":137,"title":"Anomaly detection?","user":{"login":"KrishnaPG","id":4610831,"avatar_url":"https://avatars.githubusercontent.com/u/4610831?v=3","gravatar_id":"","url":"https://api.github.com/users/KrishnaPG","html_url":"https://github.com/KrishnaPG","followers_url":"https://api.github.com/users/KrishnaPG/followers","following_url":"https://api.github.com/users/KrishnaPG/following{/other_user}","gists_url":"https://api.github.com/users/KrishnaPG/gists{/gist_id}","starred_url":"https://api.github.com/users/KrishnaPG/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/KrishnaPG/subscriptions","organizations_url":"https://api.github.com/users/KrishnaPG/orgs","repos_url":"https://api.github.com/users/KrishnaPG/repos","events_url":"https://api.github.com/users/KrishnaPG/events{/privacy}","received_events_url":"https://api.github.com/users/KrishnaPG/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-10-02T06:22:36Z","updated_at":"2015-10-02T06:22:36Z","closed_at":null,"body":"Thank you for sharing this good work.\r\n\r\nTrying to verify if this can be used for *alert when something interesting happens in a stream* scenario.\r\n\r\ni.e., can some one \"listen\" to a stream for \"data changes\"?\r\n\r\nFor example, if last 3 values are greater than the mean of the of last 8 data points then raise an alert (emit event).\r\n\r\nOr, instead of emitting an event, it could create a new data point in a child stream, so that who ever is \"listening\" on that child stream can see that data point and do whatever is necessary.\r\n\r\n````\r\nBase stream:  v1   v2   v3   v4   v5   v6   v7   v8 ....\r\nchild stream:    .     .     .      .      1     .      .   .....\r\n````\r\n\r\nI am looking for creating \"user defined functions\" as \"alert triggering\" mechanism on streams, so that user can define his own \"monitoring\" javascript function to know about interesting changes on his data.\r\n\r\nCan this package achieve such things? Creating child streams and listening on child streams for data changes etc..?\r\n\r\nAny pointers or example would be of great help."}}