James Wiseman

This message is documented quite concisely on the JSLint instructions page:

JSLintexpects that a return, break, continue, or throw statement will be followed by a } or case or default

At best, the presence unreachable code is indicative of general laziness on behalf of the developer, and, at worst, it may highlight a potential bug. Either way, JSLint is fully justified in raising the error.

The following code shows a scenario where this might arise:

function MyFunc(){
   var x = 0;
   return x;
   x++;
}

JSLint is also savvy enough to look within conditional statements…

function MyFunc(){
    var b = false;
    if (b){
        return 1;
    }
    else{
        return 2;
    }
    return 3;
}

…loops…

function MyFunc(){
    var x = 0;
    var y = 0;
    for (x=0; x<10; x++){
        if (x<5){
            break;
            y++;
        }
    }
}

…and the not often seen “throw” statement.

function MyFunc(){
    var x = 0;
    throw "MyError";
    x++;
}

This is just another way that JSLint can help you identify potential issues earlier in the development process.

A Guide To JSLint Messages

This article is one of a series on the error and warning messages produced by JSLint.