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. 

首先阅读 Reconciliation 章节的“Recursing On Children”部分，以及关于生成唯一 key 的链接讨论。为没有现有 id 的模型确定一个清晰且技术上可靠的示例，然后使用该示例和说明更新该章节；当指南在不依赖不稳定 key 的情况下涵盖常见陷阱时，即表示完成。