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JavaScript

Posted by Lana Toogood
Lana Toogood
10,158 Points

OOJS problem with class method

Hi, I'm still learning OOJS and wondering if someone can help. Every time I call this method (Item.parseDocToItem(doc)) I get "Uncaught (in promise) TypeError: Item.parseDocToItem is not a function". Is there a problem with the way I've declared this method or is it something else? Thanks

// ITEM OBJECT //
class Item {
    constructor(name, description, itemNo, size, price, imgURL, id){
        this.name = name;
        this.description = description;
        this.itemNo = itemNo;
        this.size = size;
        this.price = price;
        this.imageURL = imgURL;
        this.id = id;
        this.sold = false;
    }
    /** 
     * Returns new item with item doc data from Firestore.
     * @return  {Object}    item - new inventory item.
     */
    parseDocToItem(doc) {
        const name = doc.data().name;
        const description = doc.data().description;
        const itemNo = doc.data().itemNo;
        const size = doc.data().size;
        const price = doc.data().price;
        const imageUrl = doc.data().imageURL;
        const id = doc.id;

        let item = new Item(name, description, itemNo, size, price, imageUrl, id);
        if (typeof(item.name) != 'string' || item.name == null) {
            console.log('item name is not valid');
            return null;
        } else if (typeof(item.description) != 'string' || item.description == null) {
            console.log('item description is not valid');
            return null;
        } else if (typeof(item.itemNo) != 'string' || item.itemNo == null) {
            console.log('item no is not valid');
            return null;
        } else if (typeof(item.size) != 'string' || item.size == null) {
            console.log('item size is not valid');
            return null;
        } else if (typeof(item.price) != 'number' || item.price == null) {
            console.log('item price is not valid');
            return null;
        } else if (typeof(item.imageUrl) != 'string' || item.imageUrl == null) {
            console.log('item url is not valid')
            return null;
        } else if (typeof(item.id) != 'string' || item.id == null) {
            console.log('item id is not valid');
            return null;
        } else {
            return item;
        }
    }
}

1 Answer

scribbles
scribbles
21,173 Points
scribbles
scribbles
21,173 Points

Make sure you are instantiating a new instance of Item.

let thing = new Item('Thing', 'Brand new thing', 12, 'M', 12.99, 'https://placeimg.com/320/160/animals', 111)
// Then you can call the method on the item instance:
thing.parseDocToItem(doc);
Lana Toogood
Lana Toogood
10,158 Points

thank you, a new instance of item is instantiated in the above code but it's tricky to see, because I haven't spaced the code very well. I think I may have solved the problem though - I needed to add the "static" keyword when declaring the parseDocToItem(doc) method inside the class. Now it seems to be working!