使用JavaScript计算2个不同时间表的工作时间

Question

I have an employee that needs to serve 2 meals each meal can have a different start time and a different meal duration

I need to get the total time he worked, so let's say one meal is 60 minutes and another meal is also 60 minutes the total would be 120 minutes, but if the second meal started still in the time of the first meal it should be counted as one, so if the second meal started let's say 10 minutes after the first meal the total should be 70 min

var meals = [{
    "mealStartTime": 1478787000000, //9:00 AM
    "mealDuration": 60,
    "mealEndSearvingTime": 1478790600000
}, {
    "mealStartTime": 1478786400000, //9:10 AM
    "mealDuration": 60,    
    "mealEndSearvingTime": 1478790000000
}]

Answer 1

 // It might be a good idea to use a library like BigDecimal.js // to prevent any float point errors, or use momentjs to calculate // the distance between to times function msToMins(ms) { return ms / 1000.0 / 60.0; } // It's important to note that this algo assumes that: // * Two meals never start at the same time // * Meals always end after meals that started before them function timeWorked(meals) { // sort by start time const sortedMeals = meals.sort(m => m.mealStartTime); const result = meals.reduce((prev, curr) => { let duration = curr.mealDuration; // extract the current meal duration // if the previous meal overlaps with this one const mealsOverlap = prev.mealEndServingTime > curr.mealStartTime; if (mealsOverlap) { // calculate the distance when the previous end and this one ends // the previos meal duration was fully added in the previous cycle duration = msToMins(curr.mealEndServingTime - prev.mealEndServingTime); } // return the totalDuration accumulation, with the current meal return Object.assign({ totalDuration: prev.totalDuration + duration }, curr); }, { totalDuration: 0 }); // initialize with empty object return result.totalDuration; } const allMeals = [ { mealStartTime: 1478787000000, mealDuration: 60, mealEndServingTime: 1478790600000 }, { mealStartTime: 1478786400000, mealDuration: 60, mealEndServingTime: 1478790000000 } ]; console.log(timeWorked(allMeals)); 

Answer 2

Well, my solution is a bit lengthy. The code could probably be a bit optimized but I think the approach is right.

I'll paste the code here and you can check out this jsfiddle to see it work. Open the console though.

So here's the code:

function getTotalWorkHours(meals){
    var punches = [], startCount = 0, endCount = 0, accountablePunchPairs = [], hoursWorked = 0;

  //// Populate an array of all punches ///
  meals.forEach(function(meal) {
    punches.push({
        type:'start',
      timestamp: meal.mealStartTime, 
      inEnglishPlease: new Date(meal.mealStartTime).toLocaleString()
    });
    punches.push({
        type: 'end',
      timestamp: meal.mealEndServingTime, 
      inEnglishPlease: new Date(meal.mealEndServingTime).toLocaleString()
    });
    });

  /// Sort the punches by time ///
  punches.sort(function(a, b){
    return a.timestamp - b.timestamp;
    });


  /// Filter out only the accountable punches.
  /// We will save the punches as an array of start/end pairs.
  /// Accountable punches are those that did not occur
  /// while the employee was busy with other meals
  punches.forEach(function(punch){
    if(punch.type === 'start'){
        if(++startCount - endCount === 1) accountablePunchPairs.push([punch]);
    }
    if(punch.type === 'end'){
        if(++endCount === startCount) {
        accountablePunchPairs[accountablePunchPairs.length-1][1] = punch;
      }
    }
  });

  /// Now just calculating the total hours based
  /// on the accountable punch pairs
  accountablePunchPairs.forEach(function(punchPair){
    hoursWorked += (punchPair[1].timestamp - punchPair[0].timestamp) / 3600000;
  });

  return hoursWorked;
}

https://jsfiddle.net/friedman5764/4nyv5um0/