Javascript错误处理之抛出自定义错误

//抛出自定义异常   
function divide1 (iNum1, iNum2) {   
    try{   
        if(arguments.length != 2) {   
            throw new Error("divide() requires two arguments.");   
        } else if (typeof(iNum1) != "number" || typeof(iNum2) != "number") {   
            throw new Error("divide() requires two numbers for arguments.");   
        }   
        return iNum1.valueOf() / iNum2.valueOf();   
    } catch (e) {   
        alert(e.message);   
        return -1;   
    }   
}   
  
//模拟assert   
function assert(bCondition, sErrorMessage){   
    if(bCondition) {   
        throw new Error(sErrorMessage);   
    }   
}   
  
function divide2 (iNum1, iNum2) {   
    try{   
        assert(arguments.length != 2, "divide() requires two arguments.");   
        assert(typeof(iNum1) != "number" || typeof(iNum2) != "number", "divide() requires two numbers for arguments.");   
        assert(iNum2.valueOf() == 0, "divisor can not be zero.");   
        return iNum1.valueOf() / iNum2.valueOf();   
    } catch (e) {   
        alert(e.message);   
        return -1;   
    }    
}   
window.onload=function(){   
    divide1("a","a");   
    divide2(2,0);   
} 
//抛出自定义异常
function divide1 (iNum1, iNum2) {
    try{
        if(arguments.length != 2) {
            throw new Error("divide() requires two arguments.");
        } else if (typeof(iNum1) != "number" || typeof(iNum2) != "number") {
            throw new Error("divide() requires two numbers for arguments.");
        }
        return iNum1.valueOf() / iNum2.valueOf();
    } catch (e) {
        alert(e.message);
        return -1;
    }
}

//模拟assert
function assert(bCondition, sErrorMessage){
    if(bCondition) {
        throw new Error(sErrorMessage);
    }
}

function divide2 (iNum1, iNum2) {
    try{
        assert(arguments.length != 2, "divide() requires two arguments.");
        assert(typeof(iNum1) != "number" || typeof(iNum2) != "number", "divide() requires two numbers for arguments.");
        assert(iNum2.valueOf() == 0, "divisor can not be zero.");
        return iNum1.valueOf() / iNum2.valueOf();
    } catch (e) {
        alert(e.message);
        return -1;
    }
}
window.onload=function(){
    divide1("a","a");
    divide2(2,0);
}