JSLINQ - Distinct from multiple columns

Question

I have a working JSFiddle demo https://jsfiddle.net/u1fohjxw/

The idea is to create a unique list of items, based on multiple fields. I know the way I've implemented it could be improved, but need advice on doing it in JSLINQ.

This filtered unique list I then manually loop and add again - this could be done in JSLINQ.

Please indicate how this should be done :

var myList = [
            {FirstName:"Chris",LastName:"Pearson"},
            {FirstName:"Chris",LastName:"Pearson"},
            {FirstName:"Chris",LastName:"Sutherland"},
            {FirstName:"John",LastName:"Ronald"},
            {FirstName:"Steve",LastName:"Pinkerton"}
            ];


var exampleArray = JSLINQ(myList)
                                    .Distinct(function(item){ return item.FirstName.concat(";",item.LastName)}).items

var newList = [];     

 for (var x = 0 ; x < exampleArray.length ; x++) {
      var arraylist = exampleArray[x].split(";");
      var y= new Object();
     y.FirstName = arraylist[0];
     y.LastName = arraylist[1];
     newList.push(y);
  };                 

Answer 1

how you doing? :)

Maybe something like this helps you out:

var myList = [
            {FirstName:"Chris",LastName:"Pearson"},
            {FirstName:"Chris",LastName:"Pearson"},
            {FirstName:"Chris",LastName:"Sutherland"},
            {FirstName:"John",LastName:"Ronald"},
            {FirstName:"Steve",LastName:"Pinkerton"}
            ];

var resultList = myList.Distinct(function(x){
                                    return {
                                        FirstName: x.FirstName,
                                        LastName: x.LastName
                                    }
                                }).ToArray();

This will return an array of the object returned inside the distinct.

Edit:

Change the distinct method to this:

Distinct: function(clause) { 
        var item, dict = {}, retVal = [];
        for (var i = 0; i < this.items.length; i++) {
            item = clause.apply(this.items[i], [this.items[i]]); 
            if (dict[JSON.stringify(item)] === undefined) {
                dict[JSON.stringify(item)] = true;
                retVal.push(item);
            }
        }
        dict = null;
        return JSLINQ(retVal);
    },

It's not stress tested, I don't know how much time will take to iterate through 10k+ objects, but it's something to study and improve! :)

There's another possible fix to this if you want to try.

Cheers!