No library required. Imports a TSV (tab separated value) text file, then splits it to an array of lines, each split into an array separated by tabs.

tsv-io.js

fetch("cal.tsv")
  .then((response) => response.text())
  .then((data) => {
    //split text file by newline and tab
    //thanks to stackoverflow https://stackoverflow.com/questions/47876718/splitting-text-file-by-newlines-and-tab-in-javascript
    timetable_data = data.split("\n").map(function (ln) {
      return ln.split("\t");
  });

    //returns array of timetable data by line, separated on each line by tab separated value
  console.log(timetable_data);
});