How can I replace the last occurrence of " before ] (text-manipulation)

I'm doing some text manipulation and I want to replace the last occurrence of " (with ", "four") before ] which could be in different lines. (this essentially adds a new item in the array) e.g: array = ["one", "two", "three"] other_array = ["one", "two", "three"] array = ["one", "two", "three"] array = [ "one", "two", "three" ] array = ["one", "two", "three" ] should become array = ["one", "two", "three", "four"] other_array = ["one", "two", "three"] array = ["one", "two", "three", "four"] array = [ "one", "two", "three", "four" ] array = ["one", "two", "three", "four" ] P.S: -We are guaranteed to get a valid array so array = ["one", "two]", "three"] is invalid as strings inside the array follow this pattern [a-zA-Z0-9] so you are guaranteed to get that -Also note that they are other arrays but the one i'm interested in is an array named "array" which is unique. Tried sed

#this works for the first scenario:

sed 's/\(array.*"\)\([^"]*]\)/\1, "newItem"\2/' file.txt

# but couldn't figure out how to do this for scenarios #2 & #3