Firebase Functions, Parsing error: Unexpected token =>

Question

I'm building my first firebase function with Js to handle card payments with Checkout.com API, I've installed both checkout and firebase JavaScript SDK's and this is my index.js folder:

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);
    }
});

I think I followed the documentation correctly but for some reason, I couldn't deploy this function to firebase and I get this error:

Parsing error: Unexpected token =>

Answer 1

In package.json ,

change this

    "lint": "eslint .",

to this

    "lint": "eslint",

Answer 2

I found the solution on this page .

Essentially

Arrow functions are an ES6 feature, but here you have an async arrow function.

Async functions in general are an ES8 (or 2017) feature. Therefore you need to specify the following setting at the root of your config: parserOptions: { ecmaVersion: 8 // or 2017 }

So I needed to update my .eslintrc.js file to this

module.exports = {
  root: true,
  env: {
    es6: true,
    node: true
  },
  parserOptions: {
    ecmaVersion: 8
  },
  extends: ['eslint:recommended', 'google'],
  rules: {
    'comma-dangle': 'off',
    'quote-props': 'off',
    indent: ['error', 2]
  }
};