Question

我有以下示例数组

let myArray = [
  {name: "Sam", status: 'not_started', progress: 'start'},
  {name: "Sara", status: 'not_started', progress: 'start'},
  {name: "John", status: 'not_started', progress: 'start'},
  {name: "Eric", status: 'not_started', progress: 'start'}
]

如果所有元素都具有状态：＆＃39; not_started＆＃39;然后我想更新第一个进展到开始＆＃39;其余的就是“锁定”。所以数组看起来像这样：

let myArray = [
  {name: "Sam", status: 'not_started', progress: 'start'},
  {name: "Sara", status: 'not_started', progress: 'lock'},
  {name: "John", status: 'not_started', progress: 'lock'},
  {name: "Eric", status: 'not_started', progress: 'lock'}
]

如果第一个元素的状态已经完成＆＃39;然后第二个将开始＆＃39;和休息将会锁定＆＃39;如下所示

let myArray = [
  {name: "Sam", status: 'completed', progress: 'completed'},
  {name: "Sara", status: 'not_started', progress: 'start'},
  {name: "John", status: 'not_started', progress: 'lock'},
  {name: "Eric", status: 'not_started', progress: 'lock'}
]

此外，如果前两个已完成＆＃39;然后它看起来像下面

let myArray = [
  {name: "Sam", status: 'completed', progress: 'completed'},
  {name: "Sara", status: 'completed', progress: 'completed'},
  {name: "John", status: 'not_started', progress: 'start'},
  {name: "Eric", status: 'not_started', progress: 'lock'}
]

我试图通过myArray map并创建一系列状态和进度值，并根据状态progress: array[status]获取进度值，但这不会更新进度的进度：＆＃39;锁定＆＃ 39;正确的，因为＆＃39; not_started＆＃39;可以有进步：＆＃39;开始＆＃39;或者＆＃39;锁定＆＃39;

显然，我需要根据以前的值来更新下一个值但是没有得到它。

有谁知道我怎么能实现这个目标？

由于

Answer 1

您可以使用map()方法，在首次出现not_started状态时，您可以将this.started设置为true，并根据要更改的进度锁定。

let myArray = [
  {name: "Sam", status: 'completed', progress: 'start'},
  {name: "Sara", status: 'not_started', progress: 'start'},
  {name: "John", status: 'not_started', progress: 'start'},
  {name: "Eric", status: 'not_started', progress: 'start'}
]
  
const result = myArray.map(function(e) {
  if(e.status == 'completed') return {...e, progress: 'completed'}
  if (this.started) return { ...e, progress: 'lock'}
  if (e.status == 'not_started') this.started = true;
  return { ...e};
}, {});

console.log(result)

Answer 2

这就是你需要的吗？我希望我能正确理解你 https://jsfiddle.net/txn1cb2z/

    function iterate(arr) {

    let started_key = -1;

    for( let index in arr){
        if(arr[index].status === 'completed') {
            arr[index].progress = 'completed';
            continue;
        }

        if(arr[index].status === 'not_started'){
            arr[index].progress = 'start';
            started_key = parseInt(index);
            break;
        }
    }

    if(started_key < 0 || started_key >= arr.length -1)
        return;

    for (let i = started_key+1; i < arr.length; i++){
        arr[i].progress = 'lock';
    }

    return started_key;
}

function log(arr) {
    for (var index in arr) {
        console.log(index,arr[index].status,arr[index].progress);
    }
    console.log('------------');
}

let myArray = [
    {name: "Sam", status: 'not_started', progress: 'start'},
    {name: "Sara", status: 'not_started', progress: 'start'},
    {name: "John", status: 'not_started', progress: 'start'},
    {name: "Eric", status: 'not_started', progress: 'start'}
];

iterate(myArray);
log(myArray);

myArray[0].status = 'completed';
iterate(myArray);
log(myArray);

myArray[1].status = 'completed';
iterate(myArray);
log(myArray);

myArray[2].status = 'completed';
iterate(myArray);
log(myArray);

myArray[3].status = 'completed';
iterate(myArray);
log(myArray);

Answer 3

您的要求没有任何意义，因为第1步是：

如果所有元素都具有状态：＆＃39; not_started＆＃39;然后我想更新第一个进展到开始＆＃39;其余的就是“锁定”。所以阵列看起来像这样：

请注意，项目的所有状态字段仍然是“未启动”。所以调用一个函数来启动下一个仍然只是设置所有进度来锁定＆＃39;除了第一个。

如果步骤1为：所有项目的状态均为＆＃34; not_started＆＃34;第二项有＆＃34;锁定＆＃34;那么你可以按照你的描述实际实现其余部分。

＆＃13;

const myArray = [
  {name: "Sam", status: 'not_started', progress: 'start'},
  {name: "Sara", status: 'not_started', progress: 'start'},
  {name: "John", status: 'not_started', progress: 'start'},
  {name: "Eric", status: 'not_started', progress: 'start'}
]

const isAllNotStarted = arr =>
  arr.reduce((allNotStarted,item)=>(item.status==="not_started"&&allNotStarted),true);


const startNext = arr => {
  var status = "";
  if(isAllNotStarted(arr)&&arr[1].progress!=="lock"){
    arr = arr.map(item=>({...item,progress:"lock"}));
    arr[0].progress="start";
    status = "continue";
  }
  return arr
  .reduce(
    ([result,status],current)=>{
      if(current.progress==="start" && current.status==="not_started" && status===""){
        return [result.concat({...current,progress:"completed",status:"completed"}),"startNext"];
      }
      if(current.progress==="lock" && current.status==="not_started" && status==="startNext"){
        return [result.concat({...current,progress:"start"}),"continue"];
      }
      return [result.concat(current),status];
    },
    [[],status]
  )[0]
}

["first","next","next","start last","complete last","run over (do nothing but copy the array)"]
.reduce(
  (arr,item)=>{
    console.log(item);
    const next = startNext(arr);
    console.log(next);
    return next;
  },
  myArray
);

＆＃13;

如何根据前一个元素更新下一个元素值

3 个答案: