I have an array of strings in Javascript like `var elements = ["string1", "string2"]; The array is created dynamically so it could contain any number of strings. I want to associate a counter to each element of the array. The counter will increment or decrement during the webpage's life.

I was going to try element["string1"].counter = 1; but it didn't work.

What's a good way to implement this?

I have an array of strings in Javascript like `var elements = ["string1", "string2"]; The array is created dynamically so it could contain any number of strings. I want to associate a counter to each element of the array. The counter will increment or decrement during the webpage's life.

I was going to try element["string1"].counter = 1; but it didn't work.

What's a good way to implement this?

• javascript

• 1 Could you include the code you tried that didn't work? – Jared Farrish Commented Feb 4, 2011 at 1:32
• It's the line which said it didn't work. I am not sure what more you're asking for. – Tony_Henrich Commented Feb 4, 2011 at 3:12

4 Answers 4

If you had an array var elements = ["string1", "string2"], you could not access an element with elements["string1"], you are using the value not the index. elements[0] is the correct form of access to the element, using the numerical key.

Even then, strings are special types of object and do not appear to take additional parameters readily, at least not when I tested a moment ago. Which is odd.

You could quickly knock the array in to a set of objects with separate text and counter ponents.

var elements = ["string1", "string2"];
var elementsWithCounter = [];

for(var index = 0; index < elements.length; index++) {
    elementsWithCounter[i] = { text: elements[index], counter: 1 };
}

You could also create a "hash table" using a plain object such as:

var counter = {};

for(var i = elements.length; i--; ) {
    counter[elements[i]] = 1;
}

Then you could increment the counter with:

counter['string1'] += 1;

or

counter[elements[0]] += 1;

This might help you.

elementArray = ["string1", "string2"]

function setCounter(str, val) {
    for (var i = 0; i < elementArray.length; i++) {
        if (str === elementArray[i]) elementArray[i].counter = val;
    }
}

function getCounter(str) {
    for (var i = 0; i < elementArray.length; i++) {
        if (str === elementArray[i]) return elementArray[i].counter;
    }

}

setCounter("string1", 5);
getCounter("string1");

Alternatively just access elementArray[index].counter

Javascript primitives/built in objects can't have properties/attributes added to their prototype (i.e. String.prototype.counter = -1 doesn't work correctly). Image, String, Date, Array all can't have properties added.

Maybe instead of a string you should make it an object, similar to what Orbling has posted.