Emit event with Mongoose

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Emit event with Mongoose

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Last edited Nov 2, 2011

Created on Nov 2, 2011

The example shows how to emit a custom event after a Mongoose document is saved, using a post-save hook. The code defines `UserSchema.post('save', function() {...})`, which triggers a `'changed'` event on the document instance, passing the document and its `altered` field as arguments. After emitting, the hook deletes `this.altered` to clean up. This demonstrates Mongoose's middleware system and Node.js's `EventEmitter` pattern for observing model changes, without any visualization library or rendering data involved.

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