else if and switch

else if adds another condition to an if; JavaScript checks them top to bottom and runs the first block whose condition holds. Order matters: put the highest threshold first. A final else catches the rest.

switch (value) compares one value against fixed case labels. Each case ends with break, or execution falls through into the next case, which is a feature when several labels share a result (stack the cases) and a bug otherwise. default is the catch-all. Inside a function, return in a case does the job of break.

function httpText(code) {
  switch (code) {
    case 200:
      return "OK";
    case 404:
      return "Not found";
    default:
      return "Something else";
  }
}

Your task

Write grade(score) with an else if chain: "A" for 90 and above, "B" for 80, "C" for 70, "D" for 60, else "F". Then write dayType(day) with a switch that returns "weekend" for saturday and sunday, "weekday" for the other five, and "unknown" for anything else, ignoring capital letters.

function grade(score) {
  if (score >= 90) return "A";
  else if (score >= 80) return "B";
  else if (score >= 70) return "C";
  else if (score >= 60) return "D";
  else return "F";
}

function dayType(day) {
  switch (day.toLowerCase()) {
    case "saturday":
    case "sunday":
      return "weekend";
    case "monday":
    case "tuesday":
    case "wednesday":
    case "thursday":
    case "friday":
      return "weekday";
    default:
      return "unknown";
  }
}