How to Update Keys with new values in JavaScript with 3 Methods

In this article, we’ll look at several Update Keys with new value in JavaScript with 3 methods. If you have been dealing with Javascript, there is a possibility that you have run into this use case or a mistake that is quite similar to it: Push is not a method of the object. The variables included in an object are treated as keys by Javascript. You might occasionally need to use Javascript to dynamically alter the values of an object. In any case,

Given that JavaScript is a flexibly typed programming language and supports duck typing, updating keys in JavaScript is relatively easy. It does, however, leave room for errors, and mistakes can lead to problems. To better control and manipulate the variables within the object, keys may also be established within other objects. As we shall subsequently investigate.

So let’s cut to the chase and get to the best JavaScript methods for updating keys with new values:

Method 1: Individual Update Keys

The aforementioned bit of code depicts altering a single key value within an object; but, by just changing the key name within the obj1[“key”] call, you may change whatever value you desire.

The simplest approach to update a key-value combination in JavaScript is by using this method, however, if you need to change a lot of keys in an object, it might not be the best option.

Method 2: Update Keys With In or For Loop

We can iterate through an object in JavaScript by using the for…in a loop, which is an advancement over the previous method.

The identical solution as the one before is demonstrated here, but with the key updating taking place inside the loop:

Even while this approach achieves its objectives, there is a more… JavaScript-like method of operation. A forEach iterator!

Method 3: Update Keys With Object.keys() and forEach()

The object.keys() function may be used to retrieve all of the object’s keys, after which you can use the forEach method to iterate through each key one at a time. You can provide the changes or updated values for each key in the object that will be altered during the iteration.

Here is an example of how this will work.


Method 4: Update Keys With Object.keys() And reduce() Function

Bringing up the object.keys() method and coupling it with the reduce() function is the last approach we’ll use to alter keys in JavaScript. A  JavaScript feature that’s built-in.

The remainder of the keys will be reduced to a single value using the reduce () function, which will only return the accumulator’s most recent value.

This method differs from the others in that it produces a new object and is immutable.

For each modified value in the accumulator, this method produces a brand-new key-value object rather than overwriting the old one.

This way, as you can see, is a little more difficult, but it makes it simple to copy keys into a new object or to build an action without losing your original object.

Check out this page for further details on the reduce() functions.


Any program meant for production shouldn’t ever crash. The answer, however, does not lie in putting exception handlers everywhere. Catching exceptions is never a better choice than mitigating the potential scenarios triggering the problems.

One such instance is when the keys either absent from the object or not modified by the item’s type. In this article, we looked at a few Javascript techniques that may efficiently carry out checks and lawfully alter the object without crashing the program. You’ll notice that we utilize the if statement to prevent the application from crashing in each of the code samples.

Also Read: Kill A Process in Linux: An Introduction to the kill and pkill Commands

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