Convert single element in array of objects

Question

I am trying to convert all elements of a given key in a list of objects. The specific change is to convert an generic object to a Long object with the same values.

Input:

[obj1, obj2, obj3, ...]

Where each object looks like:

{
 key1: value1, // value1 is an object
 key2: value2
}

So the goal here is to get a very similar array, but where key1 is transformed from just object to a long object, in my example incremented by one.

Output:

[obj1, obj2, obj3]

Where each object is:

{
 key1: value1, // value1 is now a Long object
 key2: value2
}

I tried with mapping over the array and then spreading over the objects entries, but did not succeed.

Any help would be highly appreciated.

• Pointy: The code you tried really should be part of the question.
• Sergiu Paraschiv: should be a very simple map. What did you try?
• Nina Scholz: please add some real example with the wanted result, beside the code, you tried.
• psv: Thanks for the comments. I updated the question to be more specific. I also added an answer below with the final solution.

Answer 1

You don't really need to map here, unless you want to create one more new array. Simple loop would be enough, just update key1 or each object:

[obj1, obj2, obj3].forEach(obj => {
 obj.key1 = obj.key1 + 1
})

Answer 2

Since the array holds object - any modification to object reflect the actual input being passed. You need to make a copy of your object and perform the logic.

Your logic,

var input = [obj1, obj2, obj3];
var output = input.map(function(obj){
 obj.key1 = obj.key1 + 1;
 return obj;
});
console.log(input[0]===output[0]); //true

Solution:

var output = input.map(function(obj){
 var _objCopy = Object.assign({}, obj);
 _objCopy.key1 = _objCopy.key1 + 1;
 return _objCopy;
});
console.log(input[0]===output[0]); //false

Answer 3

how about dynamically first key of any object es6 way

 const myObject0 = {
 'foo1': { name: 'myNam1' },
 'foo2': { name: 'myNam2' }
 };
 const myObject1 = {
 'yo': { name: 'myNam1' },
 'boh': { name: 'myNam2' }
 };
 [myObject0, myObject1].forEach(obj => {
 let getFirstKey = Object.keys(obj)[0];
 getFirstKey = getFirstKey + 1;
 console.log(getFirstKey);
 });

Answer 4

Thanks for all the answers guys.

I ended up with the following:

Given the input

[
 {
 key1: value1, // value1 is an object
 key2: value2
 },
 {
 key1: value1, // value1 is also an object
 key2: value2
 }
]

Solution: I ended up with,

 const testvar = [obj1, obj2, obj3].map((obj) => {
 return {
 ...obj,
 key1: new Long.fromValue(obj.key1)
 }
 });
 console.log(testvar);

Which gives the output

[
 {
 key1: value1, // value1 is now a Long object
 key2: value2
 },
 {
 key1: value1, // value1 is also now a Long object
 key2: value2
 }
]