Counter not updating in javascript?

Question

I am writing a function that will take a variable then check to see if that variable is in localStorage, and if it's not, add it to localStorage. If it is in localStorage, it appends a number to the end, so that a new localStorage key gets added.

So far, I've gotten this far:

var title = "Test";
test(title);
function test(title) {
 counter = 0;
 console.log("counter = " + counter);
 if (localStorage.getItem(title)) {
 counter = counter + 1;
 title = title + " " + counter;
 console.log("found " + title);
 console.log("found " + counter);
 test(title);
 } else {
 console.log("not found " + title);
 console.log("not found " + counter);
 localStorage.setItem(title, " ");
 load();
 }
}
function load() {
 for (var key in localStorage) {
 $(".keys").append(key + "<br />");
 }
} 

That way, when I run the function say 5 times, I should have localStorage keys for:

Test, Test 1, Test 2, Test 3, Test 4

Instead, I have localStorage keys for

Test, Test 1, Test 1 1, Test 1 1 1, Test 1 1 1 1

I'm not sure why the numbers aren't adding, but here's a jsFiddle to demonstrate: http://jsfiddle.net/charlescarver/x6ALG/5/

• Jacopofar: It's a string, so you are not adding but concatenating. Use parseInt before adding
• Charlie: counter is not a string. It should be a number object, since I'm only adding 1 to the previous number, which is a number object, 0.
• JJJ: You set counter to 0 at the beginning of the function, so it's reset every time you call test().
• JJJ: I think it would work if you just moved var counter = 0 to the start of the script outside the function. Also, if title = title + " " + counter, you're appending a space and the counter number to the existing title, so if title is "Test 1" and counter is 2, you'll get "Test 1" + " " + 2 == "Test 1 2".
• JJJ: You probably didn't move it far enough (it has to be defined before you call the test() function).

Answer 1

Move the counter to outside the function so that you don't reset it to zero each time you call the function, and keep the title parameter clean so that you can perform arithmetic with the counter.

var counter = 0;
var title = "Test";
test(title);
function test(title) {
 var newTitle = title + " " + counter;
 console.log("counter = " + counter);
 if (localStorage.getItem( newTitle )) {
 counter = counter + 1;
 console.log("found " + newTitle);
 console.log("found " + counter);
 test(title);
 } else {
 console.log("not found " + newTitle);
 console.log("not found " + counter);
 localStorage.setItem( newTitle, " " );
 load();
 }
}
function load() {
 for (var key in localStorage) {
 $(".keys").append(key + "<br />");
 }
}

Note the newTitle variable.

Demo: http://jsfiddle.net/x6ALG/7/

• Charlie: Although, is there anyway for it to not add a number to the original? So that it goes Test, Test 1, Test 2... etc?
• JJJ: var newTitle = title; if( counter > 0 ) newTitle += " " + counter;
• Charlie: Perfect, here's a complete jsFiddle if anyone wants it: jsfiddle.net/charlescarver/x6ALG/10

Answer 2

Dont initialize the counter to 0 inside your function test. Make it global and intialize it outside the function. Every time your function is called, it starts the count from 0.

• Charlie: Could you provide an example.