test a java script boolean function does not work

March 13, 2023

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");
}

>Solution :

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");
}