JavaScript Try, Catch and Throw Best Practices

Below is the sample JavaScript logic. I have explained best practices how to use Try, Catch and Throw.

Java Script Error Handling best Practices

<SCRIPT LANGUAGE=”JavaScript” TYPE=”text/javascript”>
 function getMonthName (monthNumber) {
// JavaScript arrays begin with 0, not 1, so
// subtract 1.
 monthNumber = monthNumber - 1
// Create an array and fill it with 12 values
 var months = new Array(“Jan”,”Feb”,”Mar”,”Apr”,”May”,”Jun”,”Jul”,
 // If the monthNumber passed in is somewhere
 // between 0 and 11, fine; return the corresponding
 // month name.
 if (months[monthNumber] != null) {
 return months[monthNumber]
 // Otherwise, an exception occurred, so throw
 // an exception.
 250 Part IV: Interacting with Users
 21_576593 ch14.qxd 10/12/04 10:02 PM Page 250
 else {
 // This statement throws an error
 // directly to the catch block.
 throw “InvalidMonthNumber”
 // The try block wraps around the main JavaScript
 // processing code. Any JavaScript statement inside
 // the try block that generates an exception will
 // automatically throw that exception to the
 // exception handling code in the catch block.
 // The try block
 try {
 // Call the getMonthName() function with an
 // invalid month # (there is no 13th month!)
 // and see what happens.
 alert(“We never get here if an exception is thrown.”)
 // The catch block
 catch (error) {
 alert(“An “ + error + “ exception was encountered. Please contact the
 program vendor.”)
 // In a real-life situation, you might want
 // to include error-handling code here that
 // examines the exception and gives users specific
 // information (or even tries to fix the problem,
 // if possible.)

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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.