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社区首页 >问答首页 >基于布尔属性值的JavaScrip对象数组约简

问基于布尔属性值的JavaScrip对象数组约简
EN

Stack Overflow用户
提问于 2021-01-30 18:39:00
回答 2查看 168关注 0票数 1

我试图减少以下数据从视频信息到一个自定义的对象结构，删除“标签”键重复，但也保持真实的所有遇到的功能，是可用的。

初始数据如下所示：

代码语言：javascript
运行
复制
[
  {
    "label": "4320p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "2160p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "2160p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "1440p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1440p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  }
]

正如您所看到的，单个分辨率标签有许多对象，但其中一些具有HDR，而另一些则有60 for，而另一些则可能没有它们，或者两者兼有。

我想要做的是用下面的减值函数来减少这个数组。假设resolutions是上面的对象：

代码语言：javascript
运行
复制
resolutions.reduce((unique, o) => {
    if (!unique.some((obj) => obj.label === o.label)) {
      unique.push(o);
    }
    return unique;
  }, []);

这给了我以下的结构：

代码语言：javascript
运行
复制
[
  {
    "label": "4320p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "2160p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1440p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  }
]

但是，如果仔细观察，您会发现在减缩操作期间，一些布尔值与每个唯一标签键的第一个元素值合并，我最终需要启用真正的特性，即使其中只有一个是真的。2160p标签是一个很好的例子，其中实际上有一个具有HDR: true的对象，但最终我将它作为false来实现。

您知道如何用现代JavaScript来管理这种情况吗？

javascript
object
boolean
reduce
EN

回答 2

Stack Overflow用户

回答已采纳

发布于 2021-01-30 19:05:45

如果您首先使用label并在每次迭代中按.reduce分组，则会更容易：

如果true中还没有

  • ，则添加第一个对象(当前项)
  • Else，以一种方式更新存储类别的特性，如果它的一个特性不可用，并且该类别中的新当前项拥有它，则将其设置为acc。

最后，返回具有合并功能的对象的分组列表：

​

代码语言：javascript
运行
复制
const resolutions = [
  { "label": "4320p", "features": { "HDR": false, "60fps": true } },
  { "label": "2160p", "features": { "HDR": false, "60fps": true } },
  { "label": "2160p", "features": { "HDR": true, "60fps": true } },
  { "label": "1440p", "features": { "HDR": false, "60fps": true } },
  { "label": "1440p", "features": { "HDR": true, "60fps": true } },
  { "label": "1080p", "features": { "HDR": false, "60fps": true } },
  { "label": "1080p", "features": { "HDR": true, "60fps": true } },
  { "label": "1080p", "features": { "HDR": false, "60fps": true } },
  { "label": "1080p", "features": { "HDR": true, "60fps": true } },
  { "label": "720p", "features": { "HDR": false, "60fps": true } },
  { "label": "720p", "features": { "HDR": true, "60fps": true } },
  { "label": "720p", "features": { "HDR": false, "60fps": true } },
  { "label": "720p", "features": { "HDR": false, "60fps": false } },
  { "label": "720p", "features": { "HDR": true, "60fps": true } },
  { "label": "720p", "features": { "HDR": false, "60fps": false } },
  { "label": "480p", "features": { "HDR": true, "60fps": true } },
  { "label": "480p", "features": { "HDR": false, "60fps": false } },
  { "label": "480p", "features": { "HDR": false, "60fps": false } },
  { "label": "480p", "features": { "HDR": true, "60fps": false } },
  { "label": "360p", "features": { "HDR": true, "60fps": true } },
  { "label": "360p", "features": { "HDR": false, "60fps": false } },
  { "label": "360p", "features": { "HDR": false, "60fps": false } },
  { "label": "360p", "features": { "HDR": true, "60fps": false } },
  { "label": "240p", "features": { "HDR": true, "60fps": true } },
  { "label": "240p", "features": { "HDR": false, "60fps": false } },
  { "label": "240p", "features": { "HDR": false, "60fps": false } },
  { "label": "240p", "features": { "HDR": true, "60fps": false } },
  { "label": "144p", "features": { "HDR": true, "60fps": true } },
  { "label": "144p", "features": { "HDR": false, "60fps": false } },
  { "label": "144p", "features": { "HDR": false, "60fps": false } },
  { "label": "144p", "features": { "HDR": true, "60fps": false } }
];

// update category's features if any is not available yet, and the new object has it
const _getUpdatedFeatures = (currentFeatures={}, newFeatures={}) => {
  const updatedFeatures = {...currentFeatures};
  for (let [feature, currentlyAvailable] of Object.entries(currentFeatures)) {
    if(!currentlyAvailable && newFeatures[feature]===true) {
      updatedFeatures[feature] = true;
    }
  }
  return updatedFeatures;
}

// group by label and merge features availability
const res = Object.values(resolutions.reduce((acc, item) => {
  const { label } = item;
  const prev = acc[label];
  if(!prev) 
    acc[label] = item;
  else 
    acc[label] = { ...prev, features: _getUpdatedFeatures(prev.features, item.features) };
  return acc;
}, {}));

console.log(res);

​

票数 1
EN

Stack Overflow用户

发布于 2021-01-30 19:33:48

如果您希望保留您的方法，可以使用以下方法。如果您有首选项，则需要扩展if语句，以防有两个元素，一个元素的HDR设置为true，另一个元素的60 first设置为true (在这个版本中，将选择发现的第一个解析)：

​

代码语言：javascript
运行
复制
const resolutions = [{
    "label": "4320p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "2160p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "2160p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "1440p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1440p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "1080p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "720p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "480p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "360p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "240p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": true,
      "60fps": true
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": false,
      "60fps": false
    }
  },
  {
    "label": "144p",
    "features": {
      "HDR": true,
      "60fps": false
    }
  }
]


const result = resolutions.reduce((unique, o) => {
  const uniqueResolution = unique.find((resolution) => resolution.label === o.label)

  if (!uniqueResolution) {
    return unique.concat(o)
  } else if (uniqueResolution.features.HDR && uniqueResolution.features['60fps']) {
    return unique
  } else if (o.features.HDR && o.features['60fps']) {
    // swap element since there is a better one
    return unique.map((resolution) => {
      if (resolution.label === o.label) return o
      return resolution
    })
  }

  return unique
}, [])

console.log(result)

​

票数 1
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/65971779

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