PayPal Checkout (javascript) with Smart Payment Buttons create order problem

After some more digging I have found the correct format:

paypal.Buttons({    createOrder: function(data, actions) {        return actions.order.create({            purchase_units: [            {                reference_id: "PUHF",                description: "Some description",                custom_id: "Something7364",                soft_descriptor: "Great description 1",                amount: {                    currency_code: "EUR",                    value: "200.00",                    breakdown: {                        item_total: {                            currency_code: "EUR",                            value: "200.00"                        }                    }                },                items: [                    {                        name: "Item 1",                        description: "The best item ever",                        sku: "xyz-2654",                        unit_amount: {                            currency_code: "EUR",                            value: "100.00"                        },                        quantity: "1"                    },                    {                        name: "Item 2",                        description: "Not bad too",                        sku: "zdc-3942",                        unit_amount: {                            currency_code: "EUR",                            value: "50.00"                        },                        quantity: "2"                    }                ],            }        ]    });},onApprove: function(data, actions) {    return actions.order.capture().then(function(details) {        alert('Transaction completed by ' + details.payer.name.given_name);        // Call your server to save the transaction        return fetch('/api/paypal-transaction-complete', {            method: 'post',            headers: {                'content-type': 'application/json'            },            body: JSON.stringify({                orderID: data.orderID            })        });    });}}).render('#paypal-button-container');

This is an example of complete set of options:

paypal.Buttons({    createOrder: function(data, actions) {        return actions.order.create({            purchase_units: [{                reference_id: "PUHF",                description: "Sporting Goods",                custom_id: "CUST-HighFashions",                soft_descriptor: "HighFashions",                amount: {                    currency_code: "USD",                    value: "230.00",                    breakdown: {                        item_total: {                            currency_code: "USD",                            value: "180.00"                        },                        shipping: {                            currency_code: "USD",                            value: "30.00"                        },                        handling: {                            currency_code: "USD",                            value: "10.00"                        },                        tax_total: {                            currency_code: "USD",                            value: "20.00"                        },                        shipping_discount: {                            currency_code: "USD",                            value: "10"                        }                    }                },                items: [{                    name: "T-Shirt",                    description: "Green XL",                    sku: "sku01",                    unit_amount: {                         currency_code: "USD",                         value: "90.00"                    },                    tax: {                        currency_code: "USD",                        value: "10.00"                    },                    quantity: "1",                    category: "PHYSICAL_GOODS"                },                    {                    name: "Shoes",                    description: "Running, Size 10.5",                    sku: "sku02",                    unit_amount: {                         currency_code: "USD",                         value: "45.00"                    },                    tax: {                        currency_code: "USD",                        value: "5.00"                    },                    quantity: "2",                    category: "PHYSICAL_GOODS"                }                ],                shipping: {                    method: "United States Postal Service",                    address: {                        name: {                            full_name: "John",                            surname: "Doe"                        },                        address_line_1: "123 Townsend St",                        address_line_2: "Floor 6",                        admin_area_2: "San Francisco",                        admin_area_1: "CA",                        postal_code: "94107",                        country_code: "US"                    }                }            }]        })    },    onApprove: function(data, actions) {        return actions.order.capture().then(function(details) {            alert('Transaction completed by ' + details.payer.name.given_name)            // Call your server to save the transaction            return fetch('/api/paypal-transaction-complete', {                method: 'post',                headers: {                    'content-type': 'application/json'                },                body: JSON.stringify({                    orderID: data.orderID                })            })        })    }}).render('#paypal-button-container')