How to compare two object array using javascript/angularjs?

Question

I have 2 objects and I want to merge it as one object array but I need first to compare using JavaScript or AngularJS.

A = [
     {date: "2013-07-31", start_time:"2013-07-31 17:30:00+10", finish_time:"2013-07-31 20:30:00+10"},
     {date: "2013-08-03", start_time:"2013-08-03 17:00:00+10", finish_time:"2013-08-03 20:00:00+10"},
     {date: "2013-09-03", start_time:"2013-09-03 17:00:00+10", finish_time:"2013-09-03 20:00:00+10"}
    ]

B = [
     {date: "2013-07-31", start_time:"2013-07-31 17:37:49+10", finish_time:"2013-07-31 20:32:04+10"},
     {date: "2013-08-03", start_time:"2013-08-03 16:57:34+10", finish_time:"2013-08-03 20:00:57+10"}
    ]

Expected output
C = [
     {date: "2013-07-31", start_time:"late", finish_time:"on time"},
     {date: "2013-08-03", start_time:"on time", finish_time:"on time"},
    ]

I will compare first if the two object array have the same date then I will compare the start of the same date then if the start_time value on the B exceeds on A start_time then it will change to a string that it is "late". Also for finish_time if the value on B is lower than A then the string would be "too early".

Answer 1

From what I understood, basically you want to search for values inside the array B against values present in A, and compute whether the starttimes are early, late or on-time.

The solution by https://stackoverflow.com/users/1148564/joseph-serido will work perfectly, but it will take O(n^2) time. In Javascript, you can access objects by key names. If you make A and B as objects, you can leverage this behavior and make your code run with just one loop.

var A_Times = {}; //Make an Object
//Use the date as Key
A_Obj["2013-07-31"] = {start_time:"2013-07-31 17:30:00+10", finish_time:"2013-07-31 20:30:00+10"};
A_Obj["2013-08-03"] ={ start_time:"2013-08-03 17:00:00+10", finish_time:"2013-08-03 20:00:00+10"};

var B_Times = {};
B_Times["2013-07-31"] = {start_time:"2013-07-31 17:37:49+10", finish_time:"2013-07-31 20:32:04+10"};
B_Times["2013-08-03"] ={start_time:"2013-08-03 16:57:34+10", finish_time:"2013-08-03 20:00:57+10"};

var A_Days = Object.keys(A_Times); //Get all the days in A

for(var i=0; i<A_Times_Days.length; i++){
    var day = A_Times_Days[i];
    console.log(day); //Log the Key here
    var A_Data = A_Times[day];
    var B_Data = B_Times[day];
    console.log(A_Data);
    console.log(B_Data);
    //Compute punctuality here based on A_Data and B_Data
}

However, if your use case involves data for only a few days, maybe this added complexity is not worth it. Upto you to decide the trade-off. Hope it helped.

Answer 2

hi this is what i came up with, i don't know exaclty what to say. i think the code will speak for itself :p

var A = [
     {date: "2013-07-31", start_time:"2013-07-31 17:30:00+10", finish_time:"2013-07-31 20:30:00+10"},
     {date: "2013-08-03", start_time:"2013-08-03 17:00:00+10", finish_time:"2013-08-03 20:00:00+10"}
    ];

var B = [
     {date: "2013-07-31", start_time:"2013-07-31 17:37:49+10", finish_time:"2013-07-31 20:32:04+10"},
     {date: "2013-08-03", start_time:"2013-08-03 16:57:34+10", finish_time:"2013-08-03 20:00:57+10"}
     ];

function getResult()
{
    var results = [];
    for(var i = 0; i < A.length; i++)
    {
        var objA = A[i];

        for(var j = 0; j < B.length; j++)
        {
            var objB = B[j];

            if(objB.date === objA.date)
            {
                var o = {};
                o.date = objA.date;

                //if start_time of A is less than start_time of B
                if(Date.parse(objA.start_time) < Date.parse(objB.start_time))
                    o.start_time = "late";
                else
                    o.start_time = "on time";

                //if end_time of A is less than end_time of B
                if(Date.parse(objA.finish_time) < Date.parse(objB.finish_time))
                    o.finish_time = "too early";
                else
                    o.finish_time = "on time";

                results.push(o);
            }
        }
    }

    if(results.length !== 0)
        return results;

    return null;
}

P.S. it will output only objects from where the date of A is equal to the date of B

Answer 3

To me, this is really just a JavaScript issue, not really an AngularJS one.

I think something like this is what you're looking for:

const A = [
     {date: "2013-07-31", start_time:"2013-07-31 17:30:00+10", finish_time:"2013-07-31 20:30:00+10"},
     {date: "2013-08-03", start_time:"2013-08-03 17:00:00+10", finish_time:"2013-08-03 20:00:00+10"},
     {date: "2013-08-03", start_time:"2013-08-03 17:00:00+10", finish_time:"2013-08-03 20:00:00+10"}
    ];

const B = [
     {date: "2013-07-31", start_time:"2013-07-31 17:37:49+10", finish_time:"2013-07-31 20:32:04+10"},
     {date: "2013-08-03", start_time:"2013-08-03 16:57:34+10", finish_time:"2013-08-03 20:00:57+10"},
     {date: "2013-08-03", start_time:"2013-08-03 16:57:34+10", finish_time:"2013-08-03 19:00:57+10"}
    ];


let C = [];
const maxLength = Math.min(A.length, B.length);

for (let i = 0; i < maxLength; i += 1) {
  const startTimeResult = B[i].start_time > A[i].start_time ? 'late' : 'on time';
  const finishTimeResult = B[i].finish_time > A[i].finish_time ? 'on time' : 'too early';
  C[i] = { date: A[i].date, start_time: startTimeResult, finish_time: finishTimeResult };
  console.log(C[i]);
}

https://codepen.io/joseph4tw/pen/mXGeoO?editors=1012