Question

i have this function in my code and I’m using throw to create meaningful errors (rather than failing silently). However, when i structure my function this way, if i call defineSandbox() with an error, it stops the whole script.

//defineSandbox is in an object, for now i name "myObj"

var defineSandbox = function (sandboxName,SandboxDefinition) {

    //validation
    if(!is.validString(sandboxName)) {
        throw statusMessages.sandbox.invalidName;
    }
    if(!is.validFunction (SandboxDefinition)) {
        throw statusMessages.sandbox.invalidDefinition;
    }

    //...some more validation here

    //...sandbox builder code if validation passes (code wasn't returned)

    registered.sandboxes[sandboxName] = newSandbox;
};

//intentional error, non-string name
myObj.defineSandbox(false);                        

//...and so the rest of the script from here down is not executed  

//i can't build this sandbox anymore
myObj.defineSandbox('mySandbox',function(){...});  

what i would like to have is if one call fails, it gives out an error but still tries to continue to run the script. how do i structure this code so that i can achieve that?

Answer 1

Typically, you don’t want to continue execution when you manually throw a new error. If you want to have it for a logging purpose, you should consider an self-created internal solution.

However, to catch a thrown error you need to invoke a try / catch statement.

try {
    myObj.defineSandbox(false); 
} catch( ex ) {
    // execution continues here when an error was thrown. You can also inspect the `ex`ception object
}

By the way, you can also specify which kind of error you want to throw, for instance a type error or a reference error like

throw new TypeError();
throw new ReferenceError();
throw new SyntaxError();
etc.

Complete list: MDN