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React: 循环时加key的作用 #53

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leslie1943 opened this issue Nov 23, 2020 · 0 comments

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leslie1943 commented Nov 23, 2020 •

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React: 循环时加key的作用

Virtual DOM 在进行 diff算法的时候, 根据key判断是否重新渲染, 在key值唯一的情况下组件没有修改的时候,复用此节点.
由于 virtual dom 在比较的时候是同层对比, 如果没有Key, 即使是相同的节点也会删除重新创建, 如果有了key的加持,就可以复用之前的节点, 省略掉删除重建的过程
key的作用主要是为了高效的更新虚拟DOM

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