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JavaScript .map() to update array with value from another array – returns value but key is undefined

I have two arrays.

I want to update array1 by getting array2 multiple value by matching on each array’s color value.

I am using this to do the following code to do the work. Note for purposes of this question both array contents are fake data not my actual array data.

JavaScript

The code does return expected results here.

However, when I use my actual arrays, it does correctly return multiple values, but it shows color as undefined eg as follows:

JavaScript

Can anyone provide any troubleshooting hints as to why I see color = undefined for my actual arrays?

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Answer

I had to JSON.stringify the output in order to see that in fact the color values were correctly populated.

Eg this shows the color values as expected:

JavaScript

For some reason, just using:

JavaScript

Showed the color values as undefined.

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