How to Extract a Combined Object from Two JavaScript Objects with the Same Keys

Navigate the complexities of merging JavaScript objects! Discover how to effectively extract a combined object with values from two source objects while handling empty keys.
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Extracting a Combined Object from Two JavaScript Objects

If you're working with JavaScript, you may find yourself needing to merge two objects that contain the same keys but have different values. Often, one object may have values where the other has empty spaces. This can pose a challenge when you want to create a single object that pulls values from both sources while leaving empty keys as they are.

In this guide, we’ll explore how to achieve this using a straightforward approach.

The Problem at Hand

Let's look at the two objects in question:

[[See Video to Reveal this Text or Code Snippet]]

In the above example:

For key a: obj1 has a value of 1 while obj2 has a space.

For key b: obj1 has a value of 2 while obj2 has a space.

For key c: obj1 has a space while obj2 has a value of 3.

For key d: obj1 has a space while obj2 has a value of 5.

For key e: Both objects have a space.

Given these objects, the expected result should be:

[[See Video to Reveal this Text or Code Snippet]]

Notice that if both values are not empty, the one from obj1 takes precedence. If one is empty, the non-empty value is chosen. If both are empty, the result remains empty.

The Solution

Step-by-Step Breakdown

Use reduce() to iterate over these keys.

For each key, check the value in obj1. If it isn’t empty (in this case, anything that is not a space), use that value; otherwise, fallback to the value in obj2.

Build the result object incrementally inside the reduce() method.

Implementation

Here’s how this looks in code:

[[See Video to Reveal this Text or Code Snippet]]

How It Works

The reduce function starts with an empty object {} as the initial accumulator (acc).

For each curr key, we check if obj1[curr] isn't a space. If it's not (i.e., it has a value), that value is chosen; otherwise, it takes the value from obj2[curr].

At each step, we return a new object that includes the values we have determined so far.

And voilà! The result now contains the desired merged object.

Conclusion

Now you have the tools needed to tackle this common problem in JavaScript! Happy coding!