Reverse one word in a sentence

Write a function reverseWord(sentence, word) that returns the string sentence where every word equal to word is written backwards. All other words stay as they are.

• sentence has words separated by single spaces, with no spaces at the start or the end and no punctuation. It can be empty.
• word is one word: at least one letter, no spaces.
• Only a whole word that is exactly equal to word changes. Case matters: 'amazon' is not 'Amazon'.
• A longer word that has word as a substring does not change: 'Amazonian' stays 'Amazonian'.
• Every match is reversed, not only the first one.
• If there is no match, return sentence unchanged. An empty sentence gives ''.

Tip: split the sentence into words, check each word, then join the words back.