javascript - 如何为解构不存在的 key 抛出错误

Question

所以我想解构一个对象并让它在其中一个键不存在时抛出错误。我尝试了 try catch 但它没有用。我想要一个替代方案，而不是 if (variable === undefined)

let obj = {test : "test"}

try {
	let { test, asdf } = obj 
  console.log("worked")
}
catch (error) {
	console.error(error)
}

Answer 1

使用proxy如果获取了不存在的属性则抛出错误

let obj = {
  test: "test"
};

try 
{
    let { test, asdf} = getProxy(obj);
    console.log("worked");
} 
catch (error) 
{
    console.error(error)
}

function getProxy(obj) {
    return new Proxy(obj, { //create new Proxy object
        get: function(obj, prop) { //define get trap
            if( prop in obj )
            {
               return obj[prop];
            }
            else
            {
                throw new Error("No such property exists"); //throw error if prop doesn't exists
            }            
        }
    });
}

演示

let obj = {
  test: "test"
};

try 
{
    let { test, asdf} = getProxy(obj);
    console.log("worked");
} 
catch (error) 
{
    console.error(error)
}

function getProxy(obj) {
    return new Proxy(obj, {
        get: function(obj, prop) {
            if( prop in obj )
            {
               return obj[prop];
            }
            else
            {
                throw new Error("No such property exists");
            }            
        }
    });
}