TypeError: banners.forEach is not a function (Error in NewPage.js)

const form = new FormData();
        form.append('title', title);
        form.append('description', desc);
        form.append('category', categoryId);
        form.append('type', type);
        banners.forEach((banner, index) => {
            form.append('banners', banner);
        });
        products.forEach((product, index) => {
            form.append('products', product);
        });

Same error for products
TypeError: products.forEach is not a function (Error in NewPage.js)