ng build --prod is not generating vendor.bundle.js

Question

I am using node version 8.9.4, npm version 5.6.0 I have no clue why this is happening the ng build --dev is generating vendor.bundle.js while ng build --prod is not generating vendor.bundle.js here is the screenshot

output with ng build--prod [

[output with ng-build --dev]

Here is my package.json

`{
  "name": "app1",
  "version": "0.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build --prod",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular-devkit/core": "0.0.28",
    "@angular/animations": "^5.0.0",
    "@angular/common": "^5.0.0",
    "@angular/compiler": "^5.0.0",
    "@angular/core": "^5.0.0",
    "@angular/forms": "^5.0.0",
    "@angular/http": "^5.0.0",
    "@angular/platform-browser": "^5.0.0",
    "@angular/platform-browser-dynamic": "^5.0.0",
    "@angular/router": "^5.0.0",
    "core-js": "^2.4.1",
    "rxjs": "^5.5.2",
    "zone.js": "^0.8.14"
  },
  "devDependencies": {
    "@angular/cli": "1.6.3",
    "@angular/compiler-cli": "^5.0.0",
    "@angular/language-service": "^5.0.0",
    "@types/jasmine": "~2.5.53",
    "@types/jasminewd2": "~2.0.2",
    "@types/node": "~6.0.60",
    "codelyzer": "^4.0.1",
    "jasmine-core": "~2.6.2",
    "jasmine-spec-reporter": "~4.1.0",
    "karma": "~1.7.0",
    "karma-chrome-launcher": "~2.1.1",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^1.2.1",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.2",
    "ts-node": "~3.2.0",
    "tslint": "~5.7.0",
    "typescript": "~2.4.2"
  }
}

`

Answer 1

For prod builds the vendor bundle is integrated in your main bundle, because it is using the build optimizer per default.

According to the angular-cli documentation:

Total bundle sizes with Build Optimizer are smaller if there is no separate vendor chunk because having vendor code in the same chunk as app code makes it possible for Uglify to remove more unused code.

Answer 2

ng build by default don't generate vendor-chunk but instead it is combined in one main-chunk for performance and optimization purposes, you will need to add a parameter to the build command like so in order to have your vendor-chunk separated:
ng build --prod --vendor-chunk=true

see details here:

https://github.com/angular/angular-cli/wiki/build#--build-optimizer-and---vendor-chunk