CODEWITHSUNDEEP
javascriptreactjs
Yerlan Yeszhanov
Yerlan Yeszhanov

Reputation: 2439

Adding Items in object dynamically

I'm trying add items in object in for loop , but last item always rewrites values that I added before. P/S I've posted similar question before but code was too complicated , I made sample to explain my problem .

here is in jsfiddle: https://jsfiddle.net/armakarma/ykwc3xse/8/

test(){
  let array = [4,6,7,1]
  let object={}
  for (let i = 0; i < array.length; i++){
    object[array[i]]={name: 'test', id:30}
    if(array[i] > 7){
        object[array[i]]={render: true}
    } else{
        object[array[i]]={render: false}
    }
  }
  console.log(object)   
  }

Upvotes: 0

Views: 86

Answers (4)

DEBENDRA DHINDA
DEBENDRA DHINDA

Reputation: 1193

In your example, you are adding an attribute/property/key which is object[array[i]] and will be the same for that loop.

So definitely the if--else block will replace the value with the same key

You can do as follows :

function test() {
 let array = [4,6,7,10]
 let object={};
 for (let i = 0; i < array.length; i++){
  let myobj={name: 'test', id:30};

  if(array[i] > 7){
      myobj.render= true;
  } else{
      myobj.render= false;
  }
  object[array[i]] =myobj;
 }
 console.log(object);
}

test()

Upvotes: 0

benjamin Rampon
benjamin Rampon

Reputation: 1416

Another way, to do what you want is to use a reduce function : 

test() {
  let array = [4, 6, 7, 1]
  const object = array.reduce((acc, value) => {
    return { ...acc, [value]: { name: 'test', age: 30, render: value <= 7 } }
  }, {})
  console.log(object)
}

It's cleaner than use a for loop.

Upvotes: 0

Sachin
Sachin

Reputation: 179

In your if/else statements you are overwriting the object keys. Instead you should use spread operator to add properties to existing keys like this:

function test() {
  let array = [4, 6, 7, 1];
  let object = {};
  for (let i = 0; i < array.length; i++) {
    object[array[i]] = { name: 'test', id: 30 };
    if (array[i] > 7) {
      object[array[i]] = { ...object[array[i]], render: true };
    } else {
      object[array[i]] = { ...object[array[i]], render: false };
    }
  }
  console.log(object);
}

test()

Upvotes: 3

Harish Soni
Harish Soni

Reputation: 1896

You should use >= instead of >, the result you are trying to achieve is never going to be since the condition you are checking is wrong:

array = [4,6,7,1]
   object={}
  for (let i = 0; i < array.length; i++) {
    object[array[i]] = { name: "test", id: 30 };

    if (array[i] >= 7) {
      object[array[i]].render = true;
    } else {
      object[array[i]].render = false;
    }
  }
  console.log(object)

Upvotes: 0

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