生成 ID 中的 Javascript 闭包

Question

var generateID=function() {
    var prefix="uid-";
    var count=0;

    return function(){
        count+=1;
        console.log(prefix+count)
    }
}
var create = generateID();

console.log(create());
console.log(create());
console.log(create());

预期输出:uid-1uid-2uid-3

帮我解决输出中的未定义错误部分。

Answer 1

create 不返回任何东西，所以如果你 console.log(create()) 它打印 undefined

var generateID=function() {
    var prefix="uid-";
    var count=0;

    return function(){
        count+=1;
        console.log(prefix+count)
    }
}
var create = generateID();

create()
create()
create()

var generateID2 = function() {
    var prefix="uid-";
    var count=0;

    return function(){
        count+=1;
        return prefix+count
    }
}
var create2 = generateID2();

console.log(create2())
console.log(create2())
console.log(create2())