Examples for generating 'Stable, Predictable and Unique' keys

Reconciliation chapter spends a good time explaining why using the index or even Math.random() as a key is a bad idea, proceeding to suggest using an existent id as a key. When there's not an existent id, it's suggested to "add a new ID property to your model or hash some parts of the content to generate a key".

That's a very controversial issue, a lot of people do it wrong. An example of how to do it would make the chapter a lot better. It's an extensive chapter (compared to others) that seems to end up with no code conclusion. 

まず、Reconciliation章の「Recursing On Children」セクションと、一意なキーの生成についてのリンク先の議論を読んでください。既存のidを持たないモデルについて、明確で技術的に妥当な例を決め、その例と説明を使ってその章を更新してください。ガイダンスが不安定なキーに依存せず、よくある落とし穴を扱っていれば完了です。