Throwing custom exception types in JavaScript
The number of built-in in JavaScript exceptions is not that large, and they most often cannot satisfy all our needs for different types of exceptions. Therefore, JavaScript has the built-in ability to create exceptions with a custom type.
There are different ways to do this. The
simplest one is to pass an object with
the keys name and message
to throw:
try {
throw {name: 'MyError', message: 'an exception text'};
} catch (error) {
console.log(error.name); // 'MyError'
console.log(error.message); // 'an exception text'
}
Previously, we made a function that throws an exception when dividing by zero:
function div(a, b) {
if (b !== 0) {
return a / b;
} else {
throw new Error('division by zero error');
}
}
Modify this function so that it throws
an exception with some kind of type we
invented, for example,
DivisionByZeroError.
Previously, you made a function that throws an exception when trying to extract the square root of a negative number. Modify your function so that it throws an exception with the type you invented. Think carefully about the name of the exception so that this name is successful.
