Exception js code example

Example 1: exception js

function div(){
    let x = prompt('Entrez un premier nombre (numérateur)');
    let y = prompt('Entrez un deuxième nombre (dénominateur)');
    
    if(isNaN(x) || isNaN(y) || x == '' || y == ''){
        throw new Error('Merci de rentrer deux nombres');
    }else if(y == 0){
         throw new Error('Division par 0 impossible')
    }else{
        alert(x / y);
    }
}

try{
    div();
}catch(err){
    alert(err.message);
}finally{
    alert('Ce message s\'affichera quoiqu\'il arrive');
}

Example 2: js errors

JS Error Name Values:
name
Sets or returns the error name
message
Sets or returns an error message in string from
EvalError
An error has occurred in the eval() function
RangeError
A number is “out of range”
ReferenceError
An illegal reference has occurred
SyntaxError
A syntax error has occurred
TypeError
A type error has occurred
URIError
An encodeURI() error has occurred

Example 3: javascript throw new error

throw new Error("Error message here"); // Uncaught Error: Error message here

Example 4: js throw custom error

class CustomError extends Error {
  constructor(foo = 'bar', ...params) {
    // Pass remaining arguments (including vendor specific ones) to parent constructor
    super(...params)

    // Maintains proper stack trace for where our error was thrown (only available on V8)
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, CustomError)
    }

    this.name = 'CustomError'
    // Custom debugging information
    this.foo = foo
    this.date = new Date()
  }
}

try {
  throw new CustomError('baz', 'bazMessage')
} catch(e) {
  console.error(e.name)    //CustomError
  console.error(e.foo)     //baz
  console.error(e.message) //bazMessage
  console.error(e.stack)   //stacktrace
}

Example 5: javascript try catch

<html>  
<head>Exception Handling</head>  
<body>  
<script>  
try {  
   throw new Error('This is the throw keyword'); //user-defined throw statement.  
}  
catch (e) {  
  document.write(e.message); // This will generate an error message  
}  
</script>  
</body>  
</html>

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