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javascript - 使用 javascript map 将嵌套数组扩展为行

问题描述

我怎样才能使用Array.prototype.map()这个数据结构：

[
  {text: "sometext", tags: ["t1", "t2", "t3"]},
  {text: "sometext2", tags: ["t4", "t5", "t6"]}
]

进入这个数据结构？

[
  {tag: "t1", text: "sometext"},
  {tag: "t2", text: "sometext"},
  {tag: "t3", text: "sometext"},
  {tag: "t4", text: "sometext2"},
  {tag: "t5", text: "sometext2"},
  {tag: "t6", text: "sometext2"}
]

标签： javascriptnode.jsecmascript-6

解决方案

您可以采用（即将推出）Array#flatMap并映射内部数组。

var data = [{ text: "sometext", tags: ["t1", "t2", "t3"] }, { text: "sometext2", tags: ["t4", "t5", "t6"] }],
    result = data.flatMap(({ text, tags }) => tags.map(tag => ({ tag, text })));

console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

结果与Array#reduce。

var data = [{ text: "sometext", tags: ["t1", "t2", "t3"] }, { text: "sometext2", tags: ["t4", "t5", "t6"] }],
    result = data.reduce((r, { text, tags }) => [...r, ...tags.map(tag => ({ tag, text }))], []);

console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

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