Javascript /Angular JS Search Array object into Array object

Question

My problem is that:

I have got 2 Array objects like that

var array1 = [{ "id": 1, "name": "potatoe", photo="photo"}, {"id": 2, "name": "budget"}]

var array2 =  [{ "id": 1, "name": "potatoeModified"},{ "id": 3, "name": 
 "UhOhAnotherName"}, {"id": 2, "name": "budget"}]

I want to search if array1 ID object is in array 2, if is id 1 = 1 name will be replaced, If no exist like id 3 will be added.

The result will be

[{ "id": 1, "name": "potatoeModified", photo="photo"}, {"id": 2, "name": "budget"},
{ "id": 3, "name": "UhOhAnotherName"}]

I try to do that but all times I get one function with cyclomatic complexity is too high and I don't want one Super Big function for that. I think that the solution is simple but I'm so blind..... Thanks :)

Mamun · Accepted Answer · 2017-04-22 00:26:21Z

1

Try the following:

var array1 = [{ "id": 1, "name": "potatoe", "photo":"photo"}, {"id": 2, "name": "budget"}];

var array2 =  [{ "id": 1, "name": "potatoeModified"},{ "id": 3, "name": 
 "UhOhAnotherName"}, {"id": 2, "name": "budget"}];

array1.map(function(val,i){
  array2.forEach(function(v){
    if(val.id == v.id){
      val.name = v.name;
    }
    else{
      var found = array1.some(function (el) {
        return el.id === v.id;
      });
      if (!found) { array1.push(v); }
    }
  })
  
  return val;   
});

console.log(array1);

edited Apr 22, 2017 at 0:26

answered Apr 21, 2017 at 23:52

Mamun

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7 Comments

charlietfl Over a year ago

temp = v; only works because there is one missing in example...if there were more than one it would only push last missing one and not others.

Mamun Over a year ago

@charlietfl, if answer helps, I should get your vote at least.

charlietfl Over a year ago

to be honest it is not a very efficient approach since you have to do so much looping.

Mamun Over a year ago

@charlietfl, I know but here the requirements forces to do so.

charlietfl Over a year ago

no it doesn't if you map to object in one iteration and do object lookups. Number of iterations is greatly reduced

|

charlietfl · Accepted Answer · 2017-04-22 00:31:41Z

1

I would make a temporary object from each array that uses the id's as keys and stores each item as value.

Then you can loop through array 2 temporary object and either adjust name or push to array 1 depending on whether id key exist in temporary object one

var array1 = [{ "id": 1, "name": "potatoe", photo:"photo"}, {"id": 2, "name": "budget"}];
var array2 =  [{ "id": 1, "name": "potatoeModified"},{ "id": 3, "name": 
 "UhOhAnotherName"}, {"id": 2, "name": "budget"}];
 
// create temporary objects using helper function below
var tmp_1 = toObj(array1), 
    tmp_2 = toObj(array2);


// go through array 2 temp object and either adjust name or push to array 1
Object.keys(tmp_2).forEach((key)=>{       
   if(tmp_1[key]){
     // if same id exist from array one, set name
     tmp_1[key].name = tmp_2[key].name;
   }else{
     // push to array one when same id doesn't exist
     array1.push(tmp_2[key]);
   }
});

console.log(array1);
 
// helper function to prevent code duplication
function toObj(arr){
   return arr.reduce((a,c)=>{
     a[c.id] = c;
     return a;
   },{})
}

There are other ways you could do this using things like Array.prototype.find() or nested loops that might shorten the code but be slightly less efficient in the long run than creating hashmap objects

edited Apr 22, 2017 at 0:31

answered Apr 21, 2017 at 23:29

charlietfl

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2 Comments

Fabián Carrasco Over a year ago

Thanks so much, that much more clean that i have got :)

charlietfl Over a year ago

I also realized don't really even need an object for array 2... just the first one...then loop over array 2 and do similar. Still short and readable the way I did it. Get used to the idea of creating objects like this for lookups...very handy

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