根据值过滤嵌套的对象属性 [英] Filter nested object properties based on value

问题描述

请考虑以下数据:

const state = {
  tasks: {
    'ID1': {
      name: "Go to shop",
      completed: false,
    },
    'ID2': {
      name: "Get bananas",
      completed: true,
    },
    'ID3': {
      name: "Get apples",
      completed: false,
    }
  }
}

要仅检索已将 completed 设置为 true 的任务，可以使用以下代码:

To retrieve only the tasks that have completed set to true the follwoing code can be used:

function getCompletedTasks(state) {
  let tasks = {}

  Object.keys(state.tasks).forEach((key) => {
    let task = state.tasks[key]

    if (task.completed) tasks[key] = task
  })

  return tasks
}

我想知道是否有比使用 let task = {} 手动创建新的 array 更好的方法?我看过 map ，但我不确定这是否有帮助.我是新手，只是想了解是否有更干净的更好的方法.

I was wondering if there's a better way than manually creating a new array with let tasks = {}? I've looked at map but I'm not really sure this can help. I'm a newbie, just trying to understand if there's a cleaner better way.

推荐答案

您可以使用 Object.entries 获取条目数组，并根据值的是否已完成属性是真实的，然后使用 Object.fromEntries 将其变成一个对象:

You can use Object.entries to get an array of entries, filter it by whether the value's completed property is truthy, then turn it back into an object with Object.fromEntries:

const state = {
  tasks: {
    'ID1': {
      name: "Go to shop",
      completed: false,
    },
    'ID2': {
      name: "Get bananas",
      completed: true,
    },
    'ID3': {
      name: "Get apples",
      completed: false,
    }
  }
}

function getCompletedTasks(state) {
  return Object.fromEntries(
    Object.entries(state.tasks).filter(([, val]) => val.completed)
  );
}

console.log(getCompletedTasks(state));

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