예외처리 try catch throw finally

//err인자를 전달받고 에러객체는 message속성을 제공해 왜 에러가 발생했는지 설명한다. try{ var x = badVarName; } catch(err){ console.log(err.name + ': "' + err.message + '" occurred when assigning x.'); } function sqrRoot(x){ try{ if (x=="") throw {message:"Can't Square Root Nothing"}; if (isNaN(x)) throw {message:"Can't Square Root string"}; if (x<0) throw {message:"Sorry No Imagination"}; return "sqrt("+x+") = " + Math.sqrt(x); } catch(err){ return err.message; } finally{ console.log("function called"); } } function writeIt(){ console.log(sqrRoot("four")); console.log(sqrRoot("")); console.log(sqrRoot("4")); console.log(sqrRoot("-4")); } writeIt();