Need help, I'm stuck! I'm given

function counter(){}

and I read up on some materials and managed to come up with this

function counter(){
var currentValue = 0;

var increment = function(val){

currentValue  = val;
console.log(currentValue);
}

its not working and I don't really 100% understand closures yet. Would like to know what is needed in the code and how it worked. Thank you!

CodePudding user response：

The basic idea is that you create an inner function that captures the local variable and then return that function to the caller, who will call it:

function counter(){
  var currentValue = 0;

  return function(val){
    currentValue  = val;
    return currentValue;
  }  
}

// create a counter and increment by one
let c = counter()
console.log(c(1))
console.log(c(1))
console.log(c(1))

// create a new counter and increment it by 2
let e = counter()
console.log(e(2))
console.log(e(2))
console.log(e(2))

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CodePudding user response：

it looks like every time you run the function, you are updating the currentValue variable to 0. A simple solve would be to define the currentValue variable as a global variable like this:

var currentValue = 0;
function counter(val) {   //where val is a number and the number you want your counter to change by
    currentValue  = val;
console.log(currentValue);
}
}

CodePudding user response：

Maybe this code is needed

function counter(){
  var currentValue = 0;

  return function(val){
    currentValue  = val;
    return currentValue;
  }
}

var c = counter();
console.log(c(10));
console.log(c(20));