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Vue 为什么不要用 index 作为 key #86

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lovelmh13 opened this issue Jun 22, 2021 · 0 comments

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lovelmh13 commented Jun 22, 2021

与 Diff 算法有关系，Diff 算法是同层比较，可以另外这个文章：lovelmh13/One-question-a-day#37

如果用了 index，我们调换数组的顺序： ['a', 'b', 'c'] -> ['c', 'b', 'a']

虽然数组的内容是变了，但是数组的 index，还是原来的 index，并不会内容变了，就改变索引, 索引依然是 0 1 2。所以写了跟没写一样，还是会复用元素。

所以在需要改变顺序的需求下，不要使用 index 作为 key

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