How to add second array objects in first array object based on id value using angular6?

Question

This is my code

categories = [{"id":"101","name":"category1"},{"id":"102","name":"category2"},{"id":"103","name":"category3"},{"id":"104","name":"category4"}];

actions = [{"id":"201","name":"action1","category_id":"101"},{"id":"202","name":"action2","category_id":"101"},{"id":"203","name":"action3","category_id":"102"},{"id":"204","name":"action4","category_id":"104"}];

In the above categories array id value is existed in actions array. so i want to combine the two arrays into one array like the output as follows.

Output:-

finalList = [{"id":"101","name":"category1","actions":[{"id":"201","name":"action1","category_id":"101"},{"id":"202","name":"action2","category_id":"101"}]},{"id":"102","name":"category2","actions":[{"id":"203","name":"action3","category_id":"102"}]},{"id":"103","name":"category3","actions":[]},{"id":"104","name":"category4","actions":[{"id":"204","name":"action4","category_id":"104"}]}]

The posted question does not appear to include any attempt at all to solve the problem. StackOverflow expects you to try to solve your own problem first, as your attempts help us to better understand what you want. Please edit the question to show what you've tried, so as to illustrate a specific problem you're having in a minimal reproducible example. For more information, please see How to Ask and take the tour. — CertainPerformance
– CertainPerformance, Commented Sep 20, 2018 at 6:05

Pratap A.K · Accepted Answer · 2018-09-20 06:10:28Z

1

for each category find action elements and add then to category object

this.categories.forEach((element) => {
    element['actions'] = this.actions.filter((data) => data.category_id === element.id);
});
console.log(this.categories);

answered Sep 20, 2018 at 6:10

Pratap A.K

4,52715 gold badges49 silver badges81 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Sachila Ranawaka · Accepted Answer · 2018-09-20 06:09:15Z

1

use the map function along with the filter

var categories = [{"id":"101","name":"category1"},{"id":"102","name":"category2"},{"id":"103","name":"category3"},{"id":"104","name":"category4"}];

var actions = [{"id":"201","name":"action1","category_id":"101"},{"id":"202","name":"action2","category_id":"101"},{"id":"203","name":"action3","category_id":"102"},{"id":"204","name":"action4","category_id":"104"}];

var result = categories.map((item) => {
  item.action = actions.filter( ac => item.id === ac. category_id)
  return item;
})

console.log(result)

answered Sep 20, 2018 at 6:09

Sachila Ranawaka

41.6k8 gold badges62 silver badges87 bronze badges

Comments

amrender singh · Accepted Answer · 2018-09-20 06:17:24Z

You can simply use Array.reduce() to create a map of actions ,group by category Id. And than you can use Array.map() on the categories to get the desired result. The overall time complexity of this solution will be O(n).

let categories = [{"id":"101","name":"category1"},{"id":"102","name":"category2"},{"id":"103","name":"category3"},{"id":"104","name":"category4"}];

let actions = [{"id":"201","name":"action1","category_id":"101"},{"id":"202","name":"action2","category_id":"101"},{"id":"203","name":"action3","category_id":"102"},{"id":"204","name":"action4","category_id":"104"}];

let map = actions.reduce((a,curr)=>{
  (a[curr.category_id]  = a[curr.category_id] || []).push(curr);
  return a;
},{});

let result = categories.map((o)=>{
  o.actions = map[o.id] || [];
  return o;
});

console.log(result);

shehzad lakhani · Accepted Answer · 2018-09-20 06:33:03Z

0

   // Use simple for loop along with filter 
categories = [{"id":"101","name":"category1"},{"id":"102","name":"category2"},{"id":"103","name":"category3"},{"id":"104","name":"category4"}];

actions = [{"id":"201","name":"action1","category_id":"101"},{"id":"202","name":"action2","category_id":"101"},{"id":"203","name":"action3","category_id":"102"},{"id":"204","name":"action4","category_id":"104"}];

    for(var i=0;i<categories.length;i++){
        categories[i]['actions'] = actions.filter((data) => data.category_id === categories[i].id);
    };
    console.log(categories)

answered Sep 20, 2018 at 6:33

shehzad lakhani

5235 silver badges14 bronze badges

Comments

durga siva kishore mopuru · Accepted Answer · 2018-09-20 06:40:11Z

0

I am using for loops working fine.

for(var i=0;i<categories.length;i++)
{
   categories[i]["actions"]=[];
   for(var j=0;j<actions.length;j++)
   {
     if(categories[i].id==actions[j].category_id){
       categories[i]["actions"].push(actions[j]);
     }
   }
}

Any other approach without using for loops?

answered Sep 20, 2018 at 6:40

durga siva kishore mopuru

1,3576 gold badges34 silver badges57 bronze badges

Collectives™ on Stack Overflow

How to add second array objects in first array object based on id value using angular6?

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related