Let's say I have a factory like this:

const itemFactory = () => {
    const itemName = ''
    const firstMethod = () => {
        // something goes here
    }

    return { itemName, firstMethod }
}

Is there a way I can keep track of how many items I have created with that function? I want to include an index in the itemName property of each item, like this: item0, item1, item2, etc.

CodePudding user response：

You can use higher-order function to achieve that:

const createItemFactory = () => {
    let currentItem = 0;
    return () => {
        const itemName = 'item'   currentItem  ;
        const firstMethod = () => {
            // something goes here
        }

        return { itemName, firstMethod };
    }
}

you can then create an itemFactory:

const itemFactory = createItemFactory();
const item0 = itemFactory(); 
console.log(item0.itemName); // item0;
const item1 = itemFactory(); 
console.log(item1.itemName); // item1;

Read more about JavaScript closures