10 Error handling

Details

 

Error handling is the managing of errors

 

• Show error feedback

• local logging

• remote logging

 

Propagating errors refers to the process of passing an error from one part of the code to another using the throw statement with a try-catch statement.

 

 

try {

 //do whatever

} catch|(error) {

  // deal with the error
  console.log(error.message)
} finally {
   // do something everytime
}

 

Best practice for Error Handling

  • Always use try catch around code that can fail
  • Use descriptive error messages
  • avoid swallowing errors
  • log errors appropriately

 

Types of Errors

  • Syntax error
  • Reference error
  • Type Error
  • Range Error

 

Syntax Error

console.log("Hello world"

 

Reference Error

 Using a variable with declaring the variable

console.log( neverDefinedVariable )

 

Type Error

const myNumber = 12

console.log( myNumber.toUpperCase() )

// number.toUpperCase is not a function

 

 

Range Error

var myArray = [1,2,3]

console.log(myArray[10]

// Index 10 is out of bounds

 

function userDataValidation() {

    validateAge(17)
}



function validateAge(age) {

   if (age < 17 ) {
 
       throw new Error("Cant vote")
   }

}