test a java script boolean function does not work

Question

I wrote a little code snippet to check, weather a date lies in holidays or if it is a normal working day. When I use the function with a date in holidays the function seems to return true. When i check, if the function with the date is true, it seems that no true value is returned.

Exspected output is:

Holiday!
Holiday

Real output is:

Holiday!
Working Day

What am I missing? Thanks for any help.

I tried to debug my code. The if-Statement in the function gets true, so i guessed, that the function itself would be true.

//list of holidays
const ferien = {
  //Sommerferien: ["2022-07-25", "2022-09-02"],
  //Herbstferien: ["2022-10-17", "2022-10-31"],
  //Weihnachtsferien: ["2022-12-23", "2023-01-02"],
  //Osterferien: ["2023-04-03", "2023-04-06"],
  Pfingsferien: ["2023-05-30", "2023-06-07"],
};

//function to check, weather a date is in holiday or not
const getFerien2 = (date) => {
  //should run through all keys from ferien-Object
  Object.keys(ferien).forEach((element) => {
    //Test if timestamp of date lies between starting- and enddate of holiday "Pfingsferien"
    if (
      Date.parse(ferien[element][0]) <= Date.parse(date) &&
      Date.parse(date) <= Date.parse(ferien[element][1])
    ) {
      console.log("Holiday!");
      return true;
    } else {
      return false;
    }
  });
};

//Test for a specific date 
if (getFerien2("2023-05-31") === true) {
  console.log("Holiday");
} else {
  console.log("Working Day");
}

Answer 1

You're attempting to return from inside the loop, so the function never actually returns true. Use a Boolean value to track whether a holiday is found, and return that.

Other notes:

• I revised your date comparison logic to make it more intuitive.
• You don't need parentheses around single arrow function arguments.
• You don't need to compare the function return value to true. Just check it for truthiness.

//list of holidays
const ferien = {
  //Sommerferien: ["2022-07-25", "2022-09-02"],
  //Herbstferien: ["2022-10-17", "2022-10-31"],
  //Weihnachtsferien: ["2022-12-23", "2023-01-02"],
  //Osterferien: ["2023-04-03", "2023-04-06"],
  Pfingsferien: ["2023-05-30", "2023-06-07"],
};

// function to check, weather a date is in holiday or not
const getFerien2 = date => {
  let holidayFound = false;

  // Run through all keys from ferien-Object
  Object.keys(ferien).forEach(element => {

    // Test if timestamp of date lies between starting- and enddate of holiday "Pfingsferien"
    if (
      Date.parse(date) >= Date.parse(ferien[element][0]) &&
      Date.parse(date) <= Date.parse(ferien[element][1])
    ) {
      holidayFound = true;
    }
  });

  return holidayFound;
};

// Test for a specific date 
if (getFerien2("2023-05-31")) {
  console.log("Holiday");
} else {
  console.log("Working Day");
}