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我在操作 Om 应用程序中的状态时遇到问题。具体来说，我不知道如何从列表中删除项目。

这是我愚蠢的证明。这是一个被破坏的简化应用程序。https://gist.github.com/rerb/29d10959e71ba1e31e8e

显示两个按钮。按下时，它们应自行移除。

删除第一项后，尝试删除第二项时出现此错误：

   Uncaught Error: No protocol method IDeref.-deref defined for type cljs.core/PersistentArrayMap: {:id 2}

如果我先删除第二个，则在尝试删除第一个时会出现此错误：

   Uncaught Error: Assert failed: Can't put nil in on a channel

我错过了什么简单的事情？我是爱因斯特伦。

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The function remove returns a sequence, not a vector. Your state went from {:buttons [{:id 1} {:id 2}]} to {:buttons ({:id 1})}. By using into after remove you solve your problems:

(fn [buttons]
  (into [] (remove #(= button-id (:id %)) buttons))))

Note: I tried this with Chestnut and it seems to work. Also, if you are beginning with Om avoid using core.async in the beginning. It is a great complement to Om but using both while learning was too much for me to handle.

于 2015-01-18T02:06:29.343 回答