How to properly phrase a sentence in which the two key words of the OR clause use different prepositions

Question

Given these two sentences:

• The mixin is a method of adding to the properties of a Javascript class.
• The mixin is a method of removing from the properties of a Javascript class.

I'd like to combine them into a single sentence, but the verbs have different prepositions. So the use of two prepositions in the combined sentence feels clumsy:

• The mixin is a method of adding to or removing from the properties of a Javascript class.

Is there a less clumsy way to phrase this? Possibly using a single preposition? I'm actually interested in the general case or a rule, not just this specific case with which I am dealing right now.

Answer 1

You don't really need the directional prepostions "to" and "from", you can use "of" in both the original and the combined sentences.

The mixin is a method of adding or removing properties of a Javascript class.

Or use the possessive form.

The mixin is a method of adding or removing a JavaScript class's properties.

Answer 2

I suggest

The mixin is a method which modifies the properties of a Javascript class.

The suggestion is a verb, not a preposition, but is a less clumsy way to phrase it.