Angular 8, ng build compile twice and duplicate files

Question

I have started a new project in Angular 8 and when executing ng build angular compiles twice, I would like to know why

package-json:

{
  "name": "portability",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^8.1.0",
    "@angular/cdk": "^8.0.2",
    "@angular/cli": "^8.1.0",
    "@angular/common": "~8.1.0",
    "@angular/compiler": "~8.1.0",
    "@angular/core": "~8.1.0",
    "@angular/flex-layout": "^8.0.0-beta.26",
    "@angular/forms": "~8.1.0",
    "@angular/material": "^8.0.2",
    "@angular/platform-browser": "~8.1.0",
    "@angular/platform-browser-dynamic": "~8.1.0",
    "@angular/router": "~8.1.0",
    "@ngx-translate/core": "^11.0.1",
    "core-js": "^2.5.4",
    "hammerjs": "^2.0.8",
    "rxjs": "~6.5.2",
    "tslib": "^1.9.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.801.0",
    "@angular/compiler-cli": "~8.1.0",
    "@angular/language-service": "~8.1.0",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "^5.0.1",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.0.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~1.1.2",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.11.0",
    "typescript": "~3.4.5"
  }
}

node version: v10.16.0

npm version: 6.10.0

skolldev · Accepted Answer · 2019-07-10 12:08:06Z

11

This is a new feature of Angular 8, and it's called Differential Loading.

The two seperate builds you are seeing are for different browser targets - the browser the user uses determines what files angular will serve.

New browsers will get code with modern language features, while older browsers will get stable legacy code.

answered Jul 10, 2019 at 12:08

skolldev

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1 Comment

Daniel Over a year ago

thank you very much for the clarification, I researched what you said of "Differential Loading", I leave this link in case someone finds it useful: blog.angular.io/…

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