throw

function getRectArea(width, height) {
  if (isNaN(width) || isNaN(height)) {
    throw new Error("Parameter is not a number!");
  }
}

try {
  getRectArea(3, "A");
} catch (e) {
  console.error(e);
  // Expected output: Error: Parameter is not a number!
}

throw expression;

throw "Error2"; //     .
throw 42; // 42    .
throw true; // true    .

function UserException(message) {
  this.message = message;
  this.name = "UserException";
}
function getMonthName(mo) {
  mo = mo - 1; //        .(1 = 1, 12 = 12)
  var months = [
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug",
    "Sep",
    "Oct",
    "Nov",
    "Dec",
  ];
  if (months[mo] !== undefined) {
    return months[mo];
  } else {
    throw new UserException("InvalidMonthNo");
  }
}

try {
  // try 
  var myMonth = 15; // 15      
  var monthName = getMonthName(myMonth);
} catch (e) {
  monthName = "unknown";
  console.error(e.message, e.name); //     
}

/*
 * ZipCode  .
 *
 *       :
 *    12345
 *    12345-6789
 *    123456789
 *    12345 6789
 *
 *  ZipCode         ,
 *  .
 */

function ZipCode(zip) {
  zip = new String(zip);
  pattern = /[0-9]{5}([- ]?[0-9]{4})?/;
  if (pattern.test(zip)) {
    //       .
    this.value = zip.match(pattern)[0];
    this.valueOf = function () {
      return this.value;
    };
    this.toString = function () {
      return String(this.value);
    };
  } else {
    throw new ZipCodeFormatException(zip);
  }
}

function ZipCodeFormatException(value) {
  this.value = value;
  this.message = "does not conform to the expected format for a zip code";
  this.toString = function () {
    return this.value + this.message;
  };
}

/*
 *        
 *   .
 */

const ZIPCODE_INVALID = -1;
const ZIPCODE_UNKNOWN_ERROR = -2;

function verifyZipCode(z) {
  try {
    z = new ZipCode(z);
  } catch (e) {
    if (e instanceof ZipCodeFormatException) {
      return ZIPCODE_INVALID;
    } else {
      return ZIPCODE_UNKNOWN_ERROR;
    }
  }
  return z;
}

a = verifyZipCode(95060); // 95060 
b = verifyZipCode(9560); // -1 
c = verifyZipCode("a"); // -1 
d = verifyZipCode("95060"); // 95060 
e = verifyZipCode("95060 1234"); // 95060 1234 

try {
  throw n; //    .
} catch (e) {
  if (e <= 50) {
    // 1-50    
  } else {
    //     ,   
    throw e;
  }
}