根据值过滤嵌套的 object 属性

Question

Consider the following data:

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

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
}

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.

Answer 1

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));