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ViewsHow to throw "expressive" / console friendly exceptions in JavaScript?
JavaScript noob here... I'm exploring various options for throwing exceptions.
Throwing a string / primitive value
This seems to be bad practice for several reasons (catching, stacktrace, ...)
Using Error
throw new Error("bad times")
This seems to be a common approach, but I'm not a big fan because I can't easily add extra information. I can't for example do
throw new Error("bad times", { reason: strangeObject })
I could JSON.stringify the extra information, but I like when I can expand / collapse the object in the console.
From what I can tell I won't get any farther with custom exceptions / Error-subclasses.
Throwing { msg: "bad times", reason: strangeObject }
This allows me to expand / collapse strangeObject nicely in the console. For exceptions throughout my application to be consistent, I'd need to repeat the msg: part everywhere, which I'm not a fan of.
I ended up going for the last approach, just to find out that the ESLinter complains about this approach:
Expected an error object to be thrown
no-throw-literal
So, my question is basically: Can I use Error (or custom Error subclasses) in a console-friendly way, i.e. support expand/collapse?
1 answers
Answer question0
I've settled for a custom exception and a window.onerror handler:
class MyAppError extends Error {
constructor(msg, details) {
super(msg)
this.details = details
}
}
window.onerror = function(message, source, lineno, colno, error) {
if (error instanceof MyAppError) {
console.error(message, error.details)
return true
}
return false
}
function throwSomething() {
throw new MyAppError("I made a mess", {
someDetail: "a value",
otherStuff: "another value"
});
}
console.log("Hello World");
throwSomething();
(JSFiddle)
Result looks like this in Firefox and Chrome, which I'm quite happy with.
