Today I noticed that JavaScript doesn't provide an easy way to make/raise custom exceptions? while still providing an useful stacktrace.
Here is a code snippet used for the
GTA:T JavaScript interface to find the fitting stacktrace for a custom JavaScript Exception.
function Exception(name,msg) {
try {
throw new Error("")
} catch (e) {
e.stack = e.stack.split("@"+e.fileName+":").join(":");
full_stack = e.stack.split("\\n");
stack = [];
stack[0] = "Exception: "+name+"(\""+msg+"\")"
for (var i=2;i<full_stack.length-3;i++) {
entry = full_stack[i];
entry_detailed = entry.split(":");
entry_detailed[1] = entry_detailed[1] - 4; // THIS is to
// mark, that we'll "move" the source 4 lines higher,
// ... because it's eval code executed. Remove that for
// clear values.
if (i==2) lineNumber = entry_detailed[1];
stack[i] = entry_detailed.join(":");
}
return {
name:name,
message:msg,
stack:stack.join("\\n"),
lineNumber:lineNumber
};
}
}
You may use it that way:
try {
function a() {
throw new Exception("MyException","No permission!")
}
function b() {
a()
}
b()
} catch (e) {
alert(e.name+": "+e.message);
}
// Tested in Firefox
/* e:
Object {
[name] => MyException
[message] => No permission!
[stack] => Exception: MyException("No permission!")
a():3
b():6
execute():10
[lineNumber] => 3
}*/
