Search for a keyword in multiple files and return me the result with previous and following line

I’m using Node JS, I want to search for a keyword in multiple .txt files, and then that return me the previous line and the following one.

Im expecting something like this:

Cars
Scooters
Skates
Airplanes
Ships
Trucks
Bikes

Then I search for the word using some nodejs package, in this example is ship. So the package return to me the line that is upper and down. For example something like this:

{"result":"
Airplanes
Ships
Trucks
"}