Throwing a Syntax Error ???

package.json

{
  "name": "fcc-exercise-tracker",
  "version": "0.1.0",
  "description": "A REST API project, part of Free Code Camp's curriculum",
  "main": "server.js",
  "scripts": {
    "start": "node server.js"
  },
  "dependencies": {
    "express": "^4.17.1",
    "mongoose": "^5.9.13",
    "mongodb": "^3.5.7",
    "body-parser": "^1.19.0",
    "cors": "^2.8.5",
    "shortid": "^2.2.15"
  },
  "engines": {
    "node": "6.9.1"
  },
  "repository": {
    "url": "https://gomix.com/#!/project/welcome-project"
  },
  "license": "MIT",
  "keywords": [
    "node",
    "gomix",
    "express"
  ]
}

server.js

"use strict";

const express = require('express');
const app = express();
const bodyParser = require('body-parser');
const cors = require('cors');
const mongoose = require('mongoose');
const API = require("./api/api.js");


app.use(cors())

app.use(bodyParser.urlencoded({extended: false}))
app.use(bodyParser.json())


app.use(express.static('public'))

app.get('/', (req, res) => {
  res.sendFile(__dirname + '/views/index.html')
});


// Not found middleware
app.use((req, res, next) => {
  return next({status: 404, message: 'not found'})
})

// Error Handling middleware
app.use((err, req, res, next) => {
  
  let errCode, errMessage

  if (err.errors) {
    // mongoose validation error
    errCode = 400 // bad request
    const keys = Object.keys(err.errors)
    // report the first validation error
    errMessage = err.errors[keys[0]].message
  } else {
    // generic or custom error
    errCode = err.status || 500
    errMessage = err.message || 'Internal Server Error'
  }
  res.status(errCode).type('txt')
    .send(errMessage)
});


app.post("/api/exercise/newuser", async function(req, res){
  API.makeNewUser();
});


const listener = app.listen(process.env.PORT || 3000, () => {
  console.log('Your app is listening on port ' + listener.address().port)
})

var a = new API.Exercise("test", "12/20/1999")
var b = new API.Exercise("test", null)

console.log(a);console.log(b);