Why do we use "[property]: !guest[property]" when setting the state prop rather than "property: !property"?

[property] which can be ['anything'] is dynamic, meaning it can be any property on the guest object. So {property: !property} would not be dynamic. For instance, !property would be the same as !'whateverStringPropertyContains', which is always false, and false would always return an unchecked state, whereas here we need to toggle the boolean value.

Brian,

The easiest way to understand this is to circle back to the concepts of extracting a value from an object using a key.

When trying to find the name of a guest, the actual code could be written the way that you described. However, you must remember that we are storing the property as a string. Therefore, what the computer is really seeing is:

"property": !"property"

The above syntax does not work. In these instances, we must use brackets to extract the value using a string variable.

You can read more here: https://javascript.info/object#square-brackets