Files don't compress when run nodejs app in IBM cloud foundry

So I have simple express app. When it run locally, I can see js, css files got gzip compressed but when I deploy to cloud foundry, those files not compressed. The files size still the same. Anyone know the reason, how to fix it or solutions for this issue ?

const express = require('express');
const compression = require('compression');
const app = express();

app.use(compression());
app.use(express.static('./public'));

Package.json

{
  "name": "conversation-simple",
  "description": "A simple Node.js based web app which shows how to use the Conversation API to recognize user intents.",
  "version": "0.1.1",
  "main": "server.js",
  "scripts": {
    "start": "node server.js"
  },
  "dependencies": {
    "@google/chatbase": "^1.1.2",
    "body-parser": "^1.18.2",
    "botbuilder": "^3.15.0",
    "cloudant": "^1.10.0-NOTICE",
    "compression": "^1.7.3",
    "cors": "^2.8.4",
    "dotenv": "^2.0.0",
    "express": "^4.16.1",
    "gulp-rename": "^1.4.0",
    "moment": "^2.22.2",
    "nano": "^6.4.4",
    "request": "^2.87.0",
    "slick-carousel": "^1.8.1",
    "underscore": "^1.9.0",
    "universal-analytics": "^0.4.16",
    "watson-developer-cloud": "^3.5.3",
    "xml-js": "^1.6.3"
  },
  "engines": {
    "node": "8.15.x"
  }
}

from Files don't compress when run nodejs app in IBM cloud foundry