Adding properties to a single object that are missing from the data object code not working

I have a data object with key-value pairs. The data object comprises 4 properties with corresponding values. However, when data is pulled from the API, it sometimes shows 2 or 3 properties like in the case below (If the data is not available for a certain property it will not show up in the object). I want to add back the missing properties to the same object as shown below.

Data Output

var obj = {
  property1: 100
  property2: 80
  property3: 50
}

I want to check within the object if property4 exists. If not, then I can add it to the same object with a boolean value i.e. false

My code that checks all properties whether they are missing, but it is not working as expected

var obj = {
  property1: 100,
  property2: 80,
  property3: 50
}
;

const property_1 = obj.hasOwnProperty('property1');
console.log(property_1);
const property_2 = obj.hasOwnProperty('property2');
console.log(property_2);
const property_3 = obj.hasOwnProperty('property3');
console.log(property_3);
const property_4 = obj.hasOwnProperty('property4');
console.log(property_4);

if (property_1 === false || property_2 === false || property_3 === false || property_4 === false)  {

obj.property1 = false
obj.property2 = false
obj.property3 = false
obj.property4 = false
 
} 

console.log(obj)

//Console Output

{
  property1: false,
  property2: false,
  property3: false,
  property4: false
}

My Expected Result is:

{
  property1: 100,
  property2: 80,
  property3: 50,
  property4: false // Does not exist, hence it is false 
}

May I know where I am going wrong?

>Solution :

Your condition

if (property_1 === false || property_2 === false || property_3 === false || property_4 === false)  {

is true if any of the properties were missing. Then you set all the properties to false, including the ones that already had values.

You could just use a series of if statement for each property:

if (!obj.hasOwnProperty('property1')) {
    obj.property1 = false;
}
if (!obj.hasOwnProperty('property2')) {
    obj.property2 = false;
}
...

But the simple way to do this is to merge the object with an object that contains all the properties.

var obj = {
  property1: 100,
  property2: 80,
  property3: 50
};

const defaults = {
  property1: false,
  property2: false,
  property3: false,
  property4: false
};

obj = {...defaults, ...obj};

console.log(obj);