intersection of two array of objects using angularjs or javascript

Question

I have list01 like :

var list01 = [
   {
      date: **01/01/2015**,
      statut: [1,2,6],
      name: '**Name X**'
   },
   {
      date: **01/01/2015**,
      statut: [5,6],
      name: '**Name X**'
   },
   {
      date: 01/01/2016,
      statut: [5,6],
      name: 'Name Y'
   },
   ...
]

I want to generate list02 who contains all items that have the same name and date from list01

var list02 = [
   {
      date: 01/01/2015,
      name: 'Name x',
      **nbrItem: 2**
   },
   {
      date: 01/01/2016,
      statut: [5,6],
      name: 'Name Y',
      **nbrItem: 1**
   },
   ...
]

I want a better way to solve this problem

"a better way to solve this problem"... better than what? What are doing currently? — James Allardice, Mar 04 '15 at 15:36
If you're looking to **clone** your object, [**this**](http://stackoverflow.com/questions/122102/what-is-the-most-efficient-way-to-clone-an-object#answer-122190) might help you. — blex, Mar 04 '15 at 15:38
[`list02 = list01.map(yourfunctioncode)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map). — zzzzBov, Mar 04 '15 at 15:38

Austin Mullins · Accepted Answer · 2015-03-04T15:59:53.293

Please see if this fiddle does what you want. The basic idea is to create an empty list at the start, then loop through the original list. For each item in the original list, see if a matching item is already in your new list. If so, increment the nbrItem property. Otherwise, create a new object. The guts of the linked fiddle are shown below:

var len = list01.length;
var list02 = [];
for (var i = 0; i < len; i++) {
    var foundMatch = false;
    var len2 = list02.length;
    for (var j = 0; j < len2; j++) {
        if (list02[j].date == list01[i].date && list02[j].name == list01[i].name) {
            foundMatch = true;
            list02[j].nbrItem++;
            break;
        }
    }

    if (!foundMatch) {
        list02.push( {
            date: list01[i].date,
            name: list01[i].name,
            nbrItem: 1
        });
    }
}

Array.prototype.map turned out not to be a good fit in this case because you want an output with different lengths than the input. The method shown here just uses plain old for loops, which work in all browsers, even the really old ones that don't have map.

i have edited my question. list02 must regroup items that had the same date and name — Karim Oukara, Mar 04 '15 at 15:48
I completely rewrote my answer. Please let me know if this is what you wanted. — Austin Mullins, Mar 04 '15 at 16:01

Wiktor Wójcikowski · Answer 2 · 2015-03-04T16:06:10.023

2

Edited:

var list02 = [];
list01.forEach(function(item) {
  var matched = list02.filter(function(filterItem) {
    return filterItem.name==item.name && filterItem.date==item.date
  })
  if(matched.length)
    matched[0].nbrItem++
  else
    list02.push({
      date: item.date, 
      name: item.name, 
      nbrItem: 1
    });
});

edited Mar 04 '15 at 16:06

answered Mar 04 '15 at 15:53

Wiktor Wójcikowski

76
4

but you must add only items that had the same name and date into the list02 – Karim Oukara Mar 04 '15 at 15:56
Yeah, and this is exactly what it is doing, same as Austin's answer, but his answer will be more efficient for big arrays. [plnkr](http://plnkr.co/edit/MU3aoap7xONzNlzbDuiH?p=preview) – Wiktor Wójcikowski Mar 04 '15 at 16:42

intersection of two array of objects using angularjs or javascript

2 Answers2