JavaScript/ Closure

- 함수 안에서 값을 리턴하는 함수

an inner function has always access to the variables and parameters of its outer function,

even after the outer function has returned.

 

function retirement(retirementAge){
    var a = ' years left until retirement.';
    return function(yearOfBirth){
        var age = 2016 - yearOfBirth;
        console.log((retirementAge-age)+a);
    }
}

var retirementUS = retirement(66);
var retirementGermany = retirement(65);
var retirementEU = retirement(67);


retirementUS(1990);
retirement(66)(1990); 
// both give us same result
retirementGermany(1990);
retirementEU(1990);

 

 

 

 

challenge

/* rewirte this with closures
function interviewQuestion(job){
    if(job==='designer'){
        return function(name){
            console.log(name + ', can you please explain what UX design is?');
        }
    }
    else if(job==='teacher'){
        return function(name){
            console.log(name+', what subject do you teach?');
        }      
    }
    else{
        return function(name){
            console.log('hi,'+name+'! what do you do?');
        }
    }
}

var teacherQuestion = interviewQuestion('teacher');
var designerQuestion = interviewQuestion('designer');

teacherQuestion('John');
designerQuestion('Jane');
designerQuestion('Mark');

interviewQuestion('teacher')('Mark');
*/


function interviewQuestion(job) {
    return function (name) {
        if(job==='designer'){
            console.log(name + ', can you please explain what UX design is?');
        }
        else if(job==='teacher'){
            console.log(name+', what subject do you teach?');
        }
        else{ 
            console.log('hi,'+name+'! what do you do?'); 
        }
    }
} //-> 위의 함수와 달리 클로저를 이용하면 리턴문을 여러면 반복할 필요가 없다

interviewQuestion('teacher')('john');