How to combine two array objects if a key value matches in both arrays

Question

I am trying to combine two array objects with different array objects based on flight key.
If the value is matched in a2, I want to merge it with a1 and create new array.
All data in a1 must be there and matched flight details must be added from a2 to a1.

Please help me to solve this.

a1 = [{'flight':'AF1223','oring':'CDF', 'Dest':'HNG'},{'flight':'XG23','oring':'HYD', 'Dest':'MMZ'},{'flight':'PK145','oring':'XYZ', 'Dest':'PEK'}]

a2 = [{'price':230,'avail':20,'flight':'AF1223'}, {'price':430,'avail':30,'flight':'DF43'},{'price':430,'avail':30,'flight':'XG23'} ]

combine array = [{'flight':'AF1223','oring':'CDF', 'Dest':'HNG','price':230,'avail':20},{'flight':'XG23','oring':'HYD', 'Dest':'MMZ'},{'flight':'PK145','oring':'XYZ', 'Dest':'PEK','price':430,'avail':30,}]

Possible duplicate of this: http://stackoverflow.com/questions/7146217/merge-2-arrays-of-objects — Chad McGrath, Oct 03 '16 at 22:45
@LouysPatriceBessette i am new to coding and trying to get hands on, with my knowledge i tried few but dnt work so requested for help — thechoosenone, Oct 03 '16 at 22:48
@ChadMcGrath i checked that one before i raised this question, i need a way to check if value matches and only join to a1 if matches else keep it as is. — thechoosenone, Oct 03 '16 at 22:51

score 2 · Answer 1 · edited Sep 19 '17 at 11:16

I am giving you a complete solution.

a = [
  {'id':'A','oring':'CDF', 'Dest':'HNG'},
  {'id':'B','oring':'HYD', 'Dest':'MMZ'},
  {'id':'C','oring':'XYZ', 'Dest':'PEK'}];

b = [
  {'id':'A','price':230,'avail':20,}, 
  {'id':'D','price':430,'avail':30},
  {'id':'B','price':430,'avail':30} ];

// put the object D into array a
for(var i=0;i<b.length;i++) {
  var idb = b[i].id;
  var idnotfound = true;
  a.forEach(function(rowofa) {
    var ida = rowofa.id;
    if(ida == idb) {
      idnotfound = false;
    }
  });
  if(idnotfound){
    a.push(b[i]);
  }
}//for
//console.log('aa=>>',a);
//.......................................

//Match ids and then put all in array a

for(var i= 0;i<a.length;i++) {
  var ida = a[i].id;
  for(var j=0;j<b.length;j++) {
    var idb = b[j].id;
    if(ida == idb) {
      a[i].avail = b[j].avail;
      a[i].price = b[j].price;
    }//if
  } //for2
}//for1
console.log('aa=>',a);

The output will be

aa=> [ { id: 'A', oring: 'CDF', Dest: 'HNG', avail: 20, price: 230 },
       { id: 'B', oring: 'HYD', Dest: 'MMZ', avail: 30, price: 430 },
       { id: 'C', oring: 'XYZ', Dest: 'PEK' },
       { id: 'D', price: 430, avail: 30 } ]

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BrTkCa · Answer 2 · 2016-10-04T12:57:46.410

1

You can iterate over two arrays and if match push object from array2 ito array1, something like..

var a1 = [{'flight':'AF1223','oring':'CDF', 'Dest':'HNG'},{'flight':'XG23','oring':'HYD', 'Dest':'MMZ'},{'flight':'PK145','oring':'XYZ', 'Dest':'PEK'}];

var a2 = [{'price':230,'avail':20,'flight':'AF1223'}, {'price':430,'avail':30,'flight':'DF43'},{'price':430,'avail':30,'flight':'XG23'} ];

var result = a1.slice(0);

for (var i = 0 ; i < result.length ; i++){
  for (var j = 0; j < a2.length ; j++){
    if (result[i].flight == a2[j].flight){
      result[i].price = a2[j].price;
      result[i].avail = a2[j].avail;
    }
  };  
};
console.log(result);

edited Oct 04 '16 at 12:57

answered Oct 03 '16 at 22:52

BrTkCa

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3

Perhaps `Object.assign(a, b)` would be closer to the desired solution? (Or any other way of merging two objects.) Of course that'd mutate `a1`, so another array, combined, could be created, followed by (on match) `combined.push(Object.assign({}, a, b));` – Dawson Toth Oct 03 '16 at 22:55
@Lucas Costa , thank you for helping hand, but the results is not one i was trying to get, if you see the combined array of example first object will have 5 key value pairs which is made of combination of a1 and a2 since flight number matched and second object will be just 3 key value pairs because no flight number was matching. – thechoosenone Oct 03 '16 at 22:58
Thanks for suggestion @DawsonToth, I'm aggre with you and Redu asnwered based in `Object.assign`. – BrTkCa Oct 03 '16 at 23:08
Note that this still mutates `a1` because `result = a1` is an assignment by reference to the original array. `result = a1.slice(0)` would leave `a1` unchanged. – Dawson Toth Oct 04 '16 at 00:48
Thanks @DawsonToth – BrTkCa Oct 04 '16 at 12:58

Redu · Answer 3 · 2016-10-03T23:10:36.127

To match your desired output you can do as follows;

var a1 = [{'flight':'AF1223','oring':'CDF', 'Dest':'HNG'},{'flight':'XG23','oring':'HYD', 'Dest':'MMZ'},{'flight':'PK145','oring':'XYZ', 'Dest':'PEK'}],
    a2 = [{'price':230,'avail':20,'flight':'AF1223'}, {'price':430,'avail':30,'flight':'DF43'},{'price':430,'avail':30,'flight':'XG23'}],
result = a2.reduce((p,c) => (p[c.flight] && (p[c.flight] = Object.assign(p[c.flight],c)),p), a1.reduce((f,s) => (f[s.flight] = s,f),{}));
console.log(result);

How to combine two array objects if a key value matches in both arrays

3 Answers3