CODEWITHSUNDEEP
javascript
user3356809
user3356809

Reputation: 31

Denormalize a array of objects into a denormalized array

I'm trying to find a way to denormalize an array of objects in JavaScript to obtain a set of arrays. I need that structure for a table (denormalized set of data).

So, given the input: 

var data = [
    { v1: 1, v2: [ { a: 1 }, { a: 2 } ] },
    { v1: 2, v2: [ { a: 3 }, { a: 4 } ], v3: 5 },
];

I need a structure like

var data2 = [
    { v1: 1, v2_a: 1 },
    { v1: 1, v2_a: 2 },
    { v1: 2, v2_a: 3, v3: 5 },
    { v1: 2, v2_a: 4, v3: 5 }
];

Recursive way.

My first attempt is to do a full scan search in depth adding the properties in a temporal variable:

var result = [];
function aArray(data) {
    for(var i = 0; i < data.length; i++){
        var temp = {};
        for(var prop in data[i]){
            var val = data[i][prop];
            if( Object.prototype.toString.call( val ) === '[object Array]' ) {
                aArray(val);
            }else{
                temp[prop] = val;
            }
        }
        result.push(temp);
    }
}

But something doesn't work as expected

Upvotes: 3

Views: 1247

Answers (1)

Farkhat Mikhalko
Farkhat Mikhalko

Reputation: 3645

You can try this solution

var data = [
    { v1: 1, v2: [ { a: 1 }, { a: 2 } ] },
    { v1: 2, v2: [ { a: 3 }, { a: 4 } ], v3: 5 },
];

function is_a(a){
  return (typeof a == "object") && (a instanceof Array);
}
function extend(a, b){
  for(var i in b){
    a[i] = b[i];
  }
  return a;
}

Now main logic here:

var p = data.map(function(item){

  var output = {};
  var list   = [];

  for(var i in item){
    if(is_a(item[i])){
      for(var j = 0; j < item[i].length; j++){
        for(var z in item[i][j]){
          var k = {}; k[i + "_" + z] = item[i][j][z];
          list.push(k);
        }
      }
    }
    else{
      output[i] = item[i];
    }
  }    

  for(var i = 0; i < list.length; i++){
    list[i] = extend(list[i], output);
  }

  console.log(list);

});

Output: First

0: Object v1: 1 v2_a: 1

1: Object v1: 1 v2_a: 2

Second

0: Object v1: 2 v2_a: 3 v3: 5

1: Object v1: 2 v2_a: 4 v3: 5

Try demo

Upvotes: 1

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