Why is Angular 7 App having more string objects in heap in comparison to AngularJs?

{
  "name": "ClientApp",
  "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": "~7.1.0",
    "@angular/common": "~7.1.0",
    "@angular/compiler": "~7.1.0",
    "@angular/core": "~7.1.0",
    "@angular/forms": "~7.1.0",
    "@angular/http": "~7.1.0",
    "@angular/platform-browser": "~7.1.0",
    "@angular/platform-browser-dynamic": "~7.1.0",
    "@angular/router": "~7.1.0",
    "@ng-bootstrap/ng-bootstrap": "^4.0.0",
    "angular-font-awesome": "^3.1.2",
    "bootstrap": "^4.1.3",
    "core-js": "^2.5.4",
    "font-awesome": "^4.7.0",
    "jquery": "2.2.3",
    "popper.js": "^1.14.5",
    "rxjs": "~6.3.3",
    "zone.js": "~0.8.26",
    "angular": "1.5.5",
    "angular-animate": "1.5.5",
    "angular-aria": "1.5.7",
    "angular-cookies": "1.5.5",
    "angular-mocks": "1.5.5",
    "angular-sanitize": "1.5.5",
    "angular-scroll": "1.0.2",
    "angular-ui-bootstrap": "1.3.3",
    "angular-ui-grid": "4.0.4",
    "angular-ui-router": "1.0.3",
    "animate": "1.0.0",
    "animate.css": "3.5.2",
    "jquery-ui": "1.12.1",
    "jquery.inputmask": "3.3.4",
    "lodash": "4.17.11",
    "ionicons": "2.0.1",
    "moment": "2.13.0",
    "ng-mask": "3.1.1",
    "spin.js": "2.3.2",
    "stacktrace-js": "2.0.0",
    "toastr": "2.1.2",
    "waypoints": "4.0.1",
    "@angular/upgrade": "7.1.1",
    "angular2-template-loader": "0.6.2",
    "@ngrx/effects": "^6.0.1",
    "@ngrx/store": "^6.0.1",
    "@ngrx/store-devtools": "^6.0.1",
    "ngx-page-scroll": "5.0.1",
    "ngx-toastr": "9.1.1",
    "@aspnet/signalr": "1.1.0"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "0.11.0",
    "@angular/cli": "~7.1.0",
    "@angular/compiler-cli": "~7.1.0",
    "@angular/language-service": "~7.1.0",
    "@types/angular": "1.6.51",
    "@types/core-js": "2.5.0",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "10.12.11",
    "codelyzer": "~4.5.0",
    "css-loader": "0.8.0",
    "file-loader": "2.0.0",
    "imports-loader": "0.8.0",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~3.0.0",
    "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",
    "style-loader": "0.8.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.11.0",
    "typescript": "~3.1.6",
    "url-loader": "1.1.2",
    "webpack-cli": "^3.1.2"
  }
}

I had an app which was in Angular JS 1.5, Now we decided to migrate it. As part of the initial analysis, I was doing a simple POC with just 10-15 components which don’t have any complex business logic. I did copy a couple of styles from the previous app and that’s about it. With just these 15 components when I build the new app with

ng build --prod  --vendor-chunk --sourceMap=false --

I realized Angular 7 app has a very high heap size in comparison to our existing Angular JS based application. The major difference comes out from string objects which is very large in Angular 7, I just want to understand is this normal for Angular 7 or am I missing here anything.

Also with --aot option, the heap size is even more. We do have a couple of requirements like open in a new window (which again loads all app in new chrome tab with a different route). I am afraid if the user will open 3 or more tabs memory will reach around a Gb.

Is there any way we can minimize the run time heap memory especially these strings? I am attaching images from Chrome Dev Tools and my angular.json file here.

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "ClientApp": {
      "root": "ClientApp",
      "sourceRoot": "ClientApp",
      "projectType": "application",
      "prefix": "app",
      "schematics": {},
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "wwwroot/clientapp/dist",
            "index": "ClientApp/index.html",
            "main": "ClientApp/main.ts",
            "polyfills": "ClientApp/polyfills.ts",
            "tsConfig": "ClientApp/tsconfig.app.json",
            "assets": [
              "ClientApp/favicon.ico",
              "ClientApp/assets",
              {
                "glob": "**/*",
                "input": "Content",
                "ignore": [ "*.js", "*.css" ],
                "output": "Content/"
              },
            ],
            "styles": [
              "ClientApp/styles.css",
              "Content/themes/base/jquery-ui.min.css",
              "Content/dmsglobalstyles.css",
              "Content/styles-extension.css",
              "Content/responsive-styles.css"
            ],
            "scripts": [
            ]
          },
          "configurations": {
            "production": {
              "fileReplacements": [
                {
                  "replace": "ClientApp/environments/environment.ts",
                  "with": "ClientApp/environments/environment.prod.ts"
                }
              ],
              "optimization": true,
              "outputHashing": "all",
              "sourceMap": false,
              "extractCss": false,
              "namedChunks": true,
              "aot": false,
              "extractLicenses": true,
              "vendorChunk": true,
              "buildOptimizer": true
            }
          }
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "ClientApp:build"
          },
          "configurations": {
            "production": {
              "browserTarget": "ClientApp:build:production"
            }
          }
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "browserTarget": "ClientApp:build"
          }
        },
        "test": {
          "builder": "@angular-devkit/build-angular:karma",
          "options": {
            "main": "ClientApp/test.ts",
            "polyfills": "ClientApp/polyfills.ts",
            "tsConfig": "ClientApp/tsconfig.spec.json",
            "karmaConfig": "ClientApp/karma.conf.js",
            "styles": [
              "ClientApp/styles.css"
            ],
            "scripts": [],
            "assets": [
              "ClientApp/favicon.ico",
              "ClientApp/assets"
            ]
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "ClientApp/tsconfig.app.json",
              "ClientApp/tsconfig.spec.json"
            ],
            "exclude": [
              "**/node_modules/**"
            ]
          }
        }
      }
    },
    "ClientApp-e2e": {
      "root": "e2e/",
      "projectType": "application",
      "architect": {
        "e2e": {
          "builder": "@angular-devkit/build-angular:protractor",
          "options": {
            "protractorConfig": "e2e/protractor.conf.js",
            "devServerTarget": "ClientApp:serve"
          },
          "configurations": {
            "production": {
              "devServerTarget": "ClientApp:serve:production"
            }
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": "e2e/tsconfig.e2e.json",
            "exclude": [
              "**/node_modules/**"
            ]
          }
        }
      }
    }
  },
  "defaultProject": "ClientApp"
}

enter image description here

Source: AngularJS