Vercel: Unexpected token < in JSON at position 1

Hi, I'm using vercel to deploy swagger api document

This is my full code.

/* eslint-disable import/order */
const express = require('express')
const app = express()
const path = require('path')

// Router
const swaggerUi = require('swagger-ui-express')
const YAML = require('yamljs')

// Swagger
const swaggerPath = path.resolve(__dirname, './swagger.yml')
const swaggerDocument = YAML.load(swaggerPath)
// const cssOptions = require('./utils/swagger.js')

var options = {
  explorer: true
};

// API Document
app.use(
  '/apidoc',
  swaggerUi.serve,
  swaggerUi.setup(swaggerDocument, options),
)

app.use(express.json())

module.exports = app

nodejs 14
swagger-ui-express 4.3.0

Problem

When I run local environment is work. It has correctly loaded css style. CleanShot 2022-05-02 at 16 05 11

But running at Vercel Production, It's doesn't work. Dev Tools show error

DevTools failed to load source map: Could not parse content for https://metawall-backend-git-feature-express-ayugioh2003.vercel.app/apidoc/swagger-ui-bundle.js.map: Unexpected token < in JSON at position 1

DevTools failed to load source map: Could not parse content for https://metawall-backend-git-feature-express-ayugioh2003.vercel.app/apidoc/swagger-ui-standalone-preset.js.map: Unexpected token < in JSON at position 1

CleanShot 2022-05-02 at 16 01 42

CleanShot 2022-05-02 at 16 07 05

I don't understand why this error occurs, cannot load css style, I'm not sure how to fix this. I think it is vercel problem, same code deploy to Heroku, it's work! Is there any idea?

scottie1984 / swagger-ui-express

Vercel: Unexpected token < in JSON at position 1 #293

Problem