问Express/Morgan未报告Javascript致命错误

EN

var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var indexRouter = require('./routes/index');

var app = express();

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);

module.exports = app;

module.exports.removeDuplicates = function(x) {
    y = [];
    for(var i=0; i<x.length; i++) {
        if(!y.includes(x[i]))
            y.push(x[i]);
    }
    thisisanerror
    return y;
}