javascript数组转换为特定格式

Question

对象数组是动态的

Activity可以分为四种(Idle, Down, Up, Waiting)

如果事件状态为打开，下一个事件状态为关闭，但事件相同。

如何转换成我期望的输出？

var arr = [
  { Activity: 'Idle', Activity_Status: 'Open', Activity_Date: "2018-09-02T12:30:00.000Z" },
  { Activity: 'Idle', Activity_Status: 'Close', Activity_Date: "2018-09-02T14:00:00.000Z"},
  { Activity: 'Down', Activity_Status: 'Open',  Activity_Date: "2018-09-02T17:30:00.000Z" },
  { Activity: 'Down', Activity_Status: 'Close', Activity_Date: "2018-09-02T19:00:00.000Z"}
]

预期输出是:

[
  { Activity: 'Idle', From: "2018-09-02T12:30:00.000Z", To: "2018-09-02T14:30:00.000Z" },
  { Activity: 'Down', From: "2018-09-02T17:30:00.000Z", To: "2018-09-02T19:00:00.000Z" }
]

Answer 1

由于 open 状态紧跟其相应的 close 状态，使用一个简单的 for 循环，通过执行 i += 2 并且每次迭代合并当前对象和下一个对象，如下所示:

var result = [];
for(var i = 0; i < arr.length; i += 2) {
  result.push(
    { Activity: arr[i].Activity, From: arr[i].Activity_Date, To: arr[i + 1].Activity_Date }
  );
}

示例:

var arr = [ { Activity: 'Idle', Activity_Status: 'Open', Activity_Date: "2018-09-02T12:30:00.000Z" }, { Activity: 'Idle', Activity_Status: 'Close', Activity_Date: "2018-09-02T14:00:00.000Z"}, { Activity: 'Down', Activity_Status: 'Open',  Activity_Date: "2018-09-02T17:30:00.000Z" }, { Activity: 'Down', Activity_Status: 'Close', Activity_Date: "2018-09-02T19:00:00.000Z"} ];

var result = [];
for(var i = 0; i < arr.length; i += 2) {
  result.push(
    { Activity: arr[i].Activity, From: arr[i].Activity_Date, To: arr[i + 1].Activity_Date }
  );
}

console.log(result);

如果你想要一个功能性的方式来做到这一点，那么:

let result = Array.from({length: arr.length / 2}).map((_, i) =>
  ({ Activity: arr[i].Activity, From: arr[i].Activity_Date, To: arr[i + 1].Activity_Date })
);

示例:

var arr = [ { Activity: 'Idle', Activity_Status: 'Open', Activity_Date: "2018-09-02T12:30:00.000Z" }, { Activity: 'Idle', Activity_Status: 'Close', Activity_Date: "2018-09-02T14:00:00.000Z"}, { Activity: 'Down', Activity_Status: 'Open',  Activity_Date: "2018-09-02T17:30:00.000Z" }, { Activity: 'Down', Activity_Status: 'Close', Activity_Date: "2018-09-02T19:00:00.000Z"} ];

let result = Array.from({length: arr.length / 2}).map((_, i) =>
  ({ Activity: arr[i].Activity, From: arr[i].Activity_Date, To: arr[i + 1].Activity_Date })
);

console.log(result);