我正在用Js构建我的第一个firebase函数，以便用www.example.com API处理卡支付Checkout.com，我已经安装了checkout和firebase JavaScript SDK，这是我的index.js文件夹：

const functions = require("firebase-functions");
const { Checkout } = require("checkout-sdk-node");
const cko = new Checkout("sk_test_XXXXX-XXXX-XXXX");

exports.payWithToken = functions.https.onCall(async (data, context) => {
    try {
        const payment = await cko.payments.request({
            source: {
                token: data.token,
            },
            customer: {
                email: context.auth.token.email
            },
            currency: data.currency,
            amount: data.amount,
        })
        return {
            "Status": payment.status,
            "3DS-Link": payment.redirectLink,
            "Approved": approved,
            "Flagged": risk.flagged,
        };
    } catch (error) {
        console.log(error)
        throw new functions.https.HttpsError(error.name, error.message, error);
    }
});

我认为我正确地遵循了文档，但由于某种原因，我无法将此函数部署到firebase，并得到以下错误：
Parsing error: Unexpected token =>