Dynamically create array of objects, from array of objects, sorted by an object property

Question

I'm trying to match and group objects, based on a property on each object, and put them in their own array that I can use to sort later for some selection criteria. The sort method isn't an option for me, because I need to sort for 4 different values of the property.

How can I dynamically create separate arrays for the objects who have a matching property?

For example, I can do this if I know that the form.RatingNumber will be 1, 2, 3, or 4:

var ratingNumOne = [],
    ratingNumTwo,
    ratingNumThree,
    ratingNumFour;

      forms.forEach(function(form) {
      if (form.RatingNumber === 1){
         ratingNumOne.push(form);
} else if (form.RatingNumber === 2){
     ratingNumTwo.push(form)
} //and so on...    
  });

The problem is that the form.RatingNumber property could be any number, so hard-coding 1,2,3,4 will not work.

How can I group the forms dynamically, by each RatingNumber?

What's the relation between the array and the rating number? Can you specify? — 31piy
– 31piy, Commented Mar 16, 2018 at 14:00
You could sort 'form' on the 'ratingnumber' then perform a split on when the 'ratingnumbers' change and push the data from the split in the arrays. — mr deadsven
– mr deadsven, Commented Mar 16, 2018 at 14:02
The "forms" array is an array of objects, so each form has a property of RatingNumber. These could be anything from 0-1000+. — john_h
– john_h, Commented Mar 16, 2018 at 14:05

Tom Mendelson · Accepted Answer · 2018-03-16 14:07:21Z

1

try to use reduce function, something like this:

forms.reduce((result, form) => {
  result[form.RatingNumber] = result[form.RatingNumber] || []
  result[form.RatingNumber].push(form)
}
,{})

the result would be object, with each of the keys is the rating number and the values is the forms with this rating number. that would be dynamic for any count of rating number

answered Mar 16, 2018 at 14:07

Tom Mendelson

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Comments

Nina Scholz · Accepted Answer · 2018-03-16 14:00:34Z

0

You could use an object and take form.RatingNumber as key.

If you have zero based values without gaps, you could use an array instead of an object.

var ratingNumOne = [],
    ratingNumTwo = [],
    ratingNumThree = [],
    ratingNumFour = [],
    ratings = { 1: ratingNumOne, 2: ratingNumTwo, 3: ratingNumThree, 4: ratingNumFour };

// usage
ratings[form.RatingNumber].push(form);

answered Mar 16, 2018 at 14:00

Nina Scholz

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Comments

Tobias Fuchs · Accepted Answer · 2018-03-16 14:05:56Z

0

try this its a work arround:

forms.forEach(form => {
if (!window['ratingNumber' + form.RatingNumber]) window['ratingNumber' + form.RatingNumber] = [];
window['ratingNumber' + form.RatingNumber].push(form);
});

this will create the variables automaticly. In the end it will look like this:

ratingNumber1 = [form, form, form];
ratingNumber2 = [form, form];
ratingNumber100 = [form];

but to notice ratingNumber3 (for example) could also be undefined.

Just to have it said, your solution makes no sense but this version works at least.

answered Mar 16, 2018 at 14:05

Tobias Fuchs

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1 Comment

john_h Over a year ago

Which part am I not making sense? I'll update my question, I might not be asking this as clearly as I can. The reason I need to sort through these by RatingNumber is because a later part of the code needs to restrict the selection of forms to only 4 different rating periods.

Scaramouche · Accepted Answer · 2018-03-16 14:10:30Z

0

It does not matter what numbers you are getting with RatingNumber, just use it as index. The result will be an object with the RatingNumber as indexes and an array of object that have that RatingNumber as value.

//example input
var forms = [{RatingNumber:5 }, {RatingNumber:6}, {RatingNumber:78}, {RatingNumber:6}];
var results = {};
$.each(forms, function(i, form){
    if(!results[form.RatingNumber])
        results[form.RatingNumber]=[];
   	results[form.RatingNumber].push(form); 		
});
console.log(results);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

HIH

answered Mar 16, 2018 at 14:10

Scaramouche

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Comments

Slaawwa · Accepted Answer · 2018-03-16 14:35:17Z

0

// Example input data
let forms = [{RatingNumber: 1}, {RatingNumber: 4}, {RatingNumber: 2}, {RatingNumber: 1}],
    result = [];

forms.forEach(form => {
    result[form.RatingNumber]
        ? result[form.RatingNumber].push(form)
        : result[form.RatingNumber] = [form];
});

// Now `result` have all information. Next can do something else..

let getResult = index => {
    let res = result[index] || [];
    // Write your code here. For example VVVVV
    console.log(`Rating ${index}: ${res.length} count`)
    console.log(res)
}

getResult(1)
getResult(2)
getResult(3)
getResult(4)

answered Mar 16, 2018 at 14:35

Slaawwa

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Comments

frulo · Accepted Answer · 2018-03-18 22:55:04Z

0

Try to create an object with the "RatingNumber" as property:

  rating = {};
    forms.forEach(function(form) {
        if( !rating[form.RatingNumber] ){
            rating[form.RatingNumber] = []
        }
        rating[form.RatingNumber].push( form )
    })

edited Mar 18, 2018 at 22:55

answered Mar 16, 2018 at 14:05

frulo

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1 Comment

Nisarg Shah Over a year ago

Please consider adding some explanation with the answer.

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