is not comprehensive, it is a superset of JavaScript, and essentially adds optional static types and class-based object-oriented programming to the language

not at all. The difference between
ts and js lies in the specified data type, from dynamic language to static language
less and css. The difference between less and css is that less can do some calculations and transfer variables to achieve the js function that css does not have.
how can these two be compared

in essence, whether Typescript or Less, are preprocessing languages, the purpose is to enhance the functions of the original language, are supersets of the original language.