js exception code example
Example 1: try catch in javascript
try {
// Try to run this code
}
catch(err) {
// if any error, Code throws the error
}
finally {
// Always run this code regardless of error or not
//this block is optional
}
Example 2: catch error message js
try {
// test code
} catch (error) { // if error
console.error(error); // return error
}
Example 3: 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 4: javascript how to raise the error
if (..condition..) {
throw 'Error message';
}
Example 5: javascript try
var someNumber = 1;
try {
someNumber.replace("-",""); //You can't replace a int
} catch(err) {
console.log(err);
}
Example 6: 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
}