plainTextProperties: Only property whose key matches plainTextProperties uses text-diff-and-patch algorithm (google-diff-match-patch).
keyInArrayedObject: To diff between arrays that contain objects as elements, you must specify a key in the object. See https://github.com/benjamine/jsondiffpatch/blob/master/docs/arrays.md\#an-object-hash
keyOfUniqueArray: Set a key of a unique array. Unique array never include duplicated members after JSON patch.