Question

我有一个排序的JavaScript映射结构，该结构根据时间存储对象状态。
Map(key:time(inMilli), value: {object attributes})

我需要完成的是能够对照开始时间和结束时间检查地图，以获取之间的所有值的集合，而无需遍历整个地图。

//currently using something like this. But would like to not compare against entire map of times
let map = dataService.getTimeData()//returns map of all objects
let updates = getRange(someTime, someTime);

function getRange(start, stop){
  let foundValues = [];
  //if start is end or after end time
  if(start >== stop)return [start];

  //search map for values
  for([key,value] of map){
    if(key > start && key < stop)foundValues.push(key)
  }  
  return foundValues;
}

Answer 1

最后使用jstreemap并使用TreeMap并在其上限和下限功能上进行操作。这真的很容易，建议您这样做。

let map = new TreeMap();//just wanted to show that this is a TreeMap now
map = dataService.getData();

function getRange(startTime, endTime){
  let from = map.lowerBound(startTime);
  let to = map.upperBound(endTime);
  let it = from;//initialize to first value in iterator
  let foundValues = [];

  //only iterates from first object requested to last. No longer needs to search any unnecessary values. 
  while(!it.equals(to)){
    foundValues.push(it);
    it.next();
  }
  return foundValues();
}

遍历js es6映射中的指定范围

1 个答案: