Modifying the value of a property in an object array created using the map method is ineffective

Question

Modifying the value of a property in an object array created using the map method is ineffective

I have a collection of objects: https://i.sstatic.net/XNrcU.png

Within the collection, I wished to include an additional property to the objects.

To achieve this, I utilized the map function:

returnArray = returnArray.map((obj) => {
obj.active = "false"; 
return obj;
});

https://i.sstatic.net/PpiYO.png

At a later stage, I intend to modify the value of the newly added 'active' property to a different value ("true") within a separate function. However, there seems to be an issue with the value not updating.

When attempting to alter the value of a pre-existing property in the original array, the update is successful.

var array = getarrayfunction();
array[index].active = "test";              <-- Not working
array[index].originalProperty = "test";    <-- Works fine

https://i.sstatic.net/HoTIz.png

Could someone shed light on why this is happening and suggest a solution?

Appreciate your help!

javascript angular typescript

Answer 1

Answer №1

To add a new property to an existing object, use the following syntax with quotes ( obj['c'] = "false"). Click here for example

  var petArray = [{'type':'dog','name':'Buddy'},{'type':'cat','name':'Whiskers'}];

   $('button').click(function(){
     petArray = petArray.map((animal) => {
         animal['color'] = "brown"; 
         return animal;
      });
      console.log(petArray);
   })

  $('p').click(function(){
      petArray[0]['color'] = 'black';
    console.log(petArray);
  });

Answer 2

To add a new property to an existing object, use the following syntax with quotes ( obj['c'] = "false"). Click here for example

  var petArray = [{'type':'dog','name':'Buddy'},{'type':'cat','name':'Whiskers'}];

   $('button').click(function(){
     petArray = petArray.map((animal) => {
         animal['color'] = "brown"; 
         return animal;
      });
      console.log(petArray);
   })

  $('p').click(function(){
      petArray[0]['color'] = 'black';
    console.log(petArray);
  });

Modifying the value of a property in an object array created using the map method is ineffective

Answer №1

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