Filter array of objects based on a field in each object

Question

Let's say I have an array of objects like this:

[
  { "type": 121, "model": "model1" },
  { "type": 128, "model": "model2" },
  { "type": 130, "model": "model2" },
  { "type": 130, "model": "model2" }
]

And I want to filter through it and create new objects based on the model field.

With the end result being:

[
  { "type": 121, "model": "model1" }
]

[
  { "type": 128, "model": "model2" },
  { "type": 130, "model": "model2" },
  { "type": 130, "model": "model2" }
]

I'm using typescript and lodash so anything with that would be best

I tried lodash groupBy and ES6 mapping, but no success so far. I guess I could do it in a dirty way with multiple forEach loops but I'm pretty sure there is a much easier way.

can you please provide your code or https://stackblitz.com/? — Abhishek
– Abhishek, Commented Jan 4, 2019 at 10:39

Pedro Lima · Accepted Answer · 2019-01-04 10:40:39Z

2

You can use .filter, like this:

let newarray1 = array.filter(obj => obj.model === 'model1');
let newarray2 = array.filter(obj => obj.model === 'model2');
...

answered Jan 4, 2019 at 10:40

Pedro Lima

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Comments

nerding_it · Accepted Answer · 2019-01-04 10:42:36Z

1

You can simply user Array.filter function to filter out array to new array object. Here I am using variable searchModels which will have list of models which you want to filter and inside filter I am checking condition searchModels.indexOf(item.model) to check model value.

var array = [
  { "type": 121, "model": "model1" },
  { "type": 128, "model": "model2" },
  { "type": 130, "model": "model2" },
  { "type": 130, "model": "model2" }
];


var searchModels = ['model1', 'model3'];
var filteredArray = array.filter((item) => { return searchModels.indexOf(item.model) !== -1 });
console.log("Original: " , array);
console.log("Filtered: " , filteredArray);

answered Jan 4, 2019 at 10:42

nerding_it

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Comments

andrea06590 · Accepted Answer · 2019-01-04 10:47:28Z

1

You could so something like that for example :) In this case I am creating a Map, I think it's easier for search

var newData = new Map([]);

var originalData = [{"type": 130, "model": "model1"}, {"type": 130, "model": "model2"}];
var formattedData = originalData.map(obj => { 
  newData[obj.model].push(obj.type); 
});

You will get something like :

newData = ([
    [ "model1", "130" ],
    [ "model1", "128" ],
    [ "model2", "3" ]
]);

And you can get any values using the model key newData["model2"] = ["3"]

answered Jan 4, 2019 at 10:47

andrea06590

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Comments

arizafar · Accepted Answer · 2019-01-04 11:21:58Z

1

you can use Array.prototype.reduce method to group all.

let array = [
  { "type": 121, "model": "model1" },
  { "type": 128, "model": "model2" },
  { "type": 130, "model": "model2" },
  { "type": 130, "model": "model2" }
]

let all = [...array.reduce((acc, curr) => {
  acc.has(curr.model) ? acc.set(curr.model, [...acc.get(curr.model), curr]): acc.set(curr.model, [curr]);
  return acc;
}, new Map()).values()];
console.log(...all)

answered Jan 4, 2019 at 11:21

arizafar

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Comments

Ganesh · Accepted Answer · 2019-01-04 12:05:49Z

1

try this @raulicious,

var arrayList= [
  { "type": 121, "model": "model1" },
  { "type": 128, "model": "model2" },
  { "type": 130, "model": "model2" },
  { "type": 131, "model": "model2" }
];


   var filteredArray = [];
   var filtered = [];
   
   arrayList.sort((a, b) => {
         if(a.model == b.model) {
             filtered.push(b);
         } else {
             filtered.push(b);
             filteredArray.push(filtered);
             filtered = [];
           }
       filtered.push(a);
       filteredArray.push(filtered);
     });
    console.log(filteredArray);

I know this has some redundant code, I am trying to reduce that soon

edited Jan 4, 2019 at 12:05

answered Jan 4, 2019 at 11:22

Ganesh

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Comments

Rohit.007 · Accepted Answer · 2019-01-04 11:15:15Z

0

See, if this help with lodash

var data = [
  { "type": 121, "model": "model1" },
  { "type": 128, "model": "model2" },
  { "type": 130, "model": "model2" },
  { "type": 130, "model": "model2" }
];

var grouped = _.groupBy(data, function(item) {
  return item.model;
});

console.log(grouped);

<script src='https://cdn.jsdelivr.net/lodash/4.17.2/lodash.min.js'></script>

answered Jan 4, 2019 at 11:15

Rohit.007

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