how to throw an error in a try with a message and catch it using js code example

Example 1: catch error message js

try {
  // test code
} catch (error) { // if error
  console.error(error); // return error
}

Example 2: try catch throwing error in javascript

let json = '{ "age": 30 }'; // incomplete data

try {

  let user = JSON.parse(json); // <-- no errors
  alert( user.name ); // no name!

} catch (e) {
  alert( "doesn't execute" );
}