Javascript closures in generat ID

user_19317459 0
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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());

Expected output: uid-1 uid-2 uid-3

Help me in undefined error part in output.

closures javascript
2 Answers

create doesn't return anything so if you console.log(create()) it prints 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())

user_143268990

The create function does not return any value. This is why console.log(create()); calls log undefined.

return function() {
    count+=1;
    return prefix+count;
}
user_8481640
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