Angular 9 Ivy compile error

I’ve enabled Angular Ivy support in my project and after refreshing my node_modules/package-lock.json files I had this error on the next ng serve after npm install

Expected result

Should (pre)compile without any error / ngx-select-dropdown needs Ivy support.

Actual result

ERROR in node_modules/ngx-select-dropdown/dist/ngx-select-dropdown.module.d.ts:1:22 - error NG6002: 
Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class. 

This likely means that the library (ngx-select-dropdown) which declares SelectDropDownModule 
has not been processed correctly by ngcc, or is not compatible with Angular Ivy. 
Check if a newer version of the library is available, and update if so. 
Also consider checking with the library's authors to see if the library is expected to be compatible with Ivy.

1 export declare class SelectDropDownModule {

If I add following parameters to package.json --> scripts --> "postinstall": "ngcc --properties es2015 es5 browser module main --first-only --create-ivy-entry-points", ng serve will work again but I got following errors on first npm install:

Error: Failed to compile entry-point ngx-select-dropdown (module as esm5) due to compilation errors:
node_modules/@angular/common/common.d.ts:115:22 - error NG6002: Appears in the NgModule.imports of SelectDropDownModule,
but could not be resolved to an NgModule class.

This likely means that the library (@angular/common) which declares CommonModule 
has not been processed correctly by ngcc, or is not compatible with Angular Ivy. Check if a newer version of the
library is available, and update if so. Also consider checking with the library's authors to see if the library is expected to be compatible with Ivy.

115 export declare class CommonModule {
                         ~~~~~~~~~~~~
node_modules/@angular/forms/forms.d.ts:2574:22 - error NG6002: Appears in the NgModule.imports of 
SelectDropDownModule, but could not be resolved to an NgModule class.

This likely means that the library (@angular/forms) which declares FormsModule has not been processed correctly by ngcc, 
or is not compatible with Angular Ivy. 
Check if a newer version of the library is available, and update if so. Also consider checking with the library's authors 
to see if the library is expected to be compatible with Ivy.

2574 export declare class FormsModule {

Steps to reproduce

1. My package.json:

{
    "name": "xxx",
    "version": "0.0.0",
    "scripts": {
        "ng": "ng",
        "start": "ng serve",
        "_comment": "ng serve --proxy-config proxy.conf.json",
        "build": "ng build",
        "test": "ng test",
        "lint": "ng lint",
        "e2e": "ng e2e",
        "compodoc": "npx compodoc -p src/tsconfig.app.json",
        "postinstall": "ngcc"
    },
    "private": true,
    "dependencies": {
        "@angular/animations": "~9.1.12",
        "@angular/cdk": "^9.2.4",
        "@angular/common": "~9.1.12",
        "@angular/compiler": "~9.1.12",
        "@angular/core": "~9.1.12",
        "@angular/forms": "~9.1.12",
        "@angular/localize": "^9.1.12",
        "@angular/material": "^9.2.4",
        "@angular/platform-browser": "~9.1.12",
        "@angular/platform-browser-dynamic": "~9.1.12",
        "@angular/pwa": "^0.1001.0",
        "@angular/router": "~9.1.12",
        "@angular/service-worker": "~9.1.12",
        "@fortawesome/angular-fontawesome": "^0.6.1",
        "@fullcalendar/adaptive": "^5.3.1",
        "@fullcalendar/angular": "^5.3.1",
        "@fullcalendar/core": "^5.3.1",
        "@fullcalendar/daygrid": "^5.3.2",
        "@fullcalendar/interaction": "^5.3.1",
        "@fullcalendar/list": "^5.3.1",
        "@fullcalendar/resource-timeline": "^5.3.1",
        "@fullcalendar/timegrid": "^5.3.1",
        "@ng-bootstrap/ng-bootstrap": "^6.2.0",
        "@ng-select/ng-select": "^4.0.4",
        "@ngx-loading-bar/core": "^4.2.0",
        "@ngx-loading-bar/http-client": "^4.2.0",
        "@ngx-translate/core": "^12.1.2",
        "@ngx-translate/http-loader": "^5.0.0",
        "@types/jspdf": "^1.3.3",
        "angular-calendar": "^0.28.16",
        "angular-disable-browser-back-button": "^1.0.2",
        "angular-dual-listbox": "^5.0.1",
        "angularx-flatpickr": "^6.4.0",
        "bootstrap": "^4.5.2",
        "core-js": "^3.6.5",
        "flag-icon-css": "^3.5.0",
        "flatpickr": "^4.6.6",
        "font-awesome": "^4.7.0",
        "hammerjs": "^2.0.8",
        "http-server": "^0.12.3",
        "i18n-iso-countries": "^6.2.2",
        "jspdf": "^2.1.1",
        "jspdf-autotable": "^3.5.12",
        "just-detect-adblock": "^1.0.0",
        "lodash": "^4.17.20",
        "lowdb": "^1.0.0",
        "moment": "^2.27.0",
        "moment-timezone": "^0.5.31",
        "ng-click-outside": "^7.0.0",
        "ng-sidebar": "^9.4.2",
        "ng-simple-slideshow": "^1.2.9",
        "ngx-bottom-nav": "^0.5.0",
        "ngx-cookie-service": "^11.0.2",
        "ngx-device-detector": "^2.0.0",
        "ngx-mat-select-search": "^3.1.0",
        "ngx-pagination": "^5.0.0",
        "ngx-select-dropdown": "^1.5.0",
        "ngx-timer": "^1.0.6",
        "node-forge": "^0.10.0",
        "node-sass": "^4.12.0",
        "numeral": "^2.0.6",
        "opencage-api-client": "^0.10.0",
        "rxjs": "~6.6.3",
        "saturn-datepicker": "^8.0.5",
        "tippy.js": "^6.2.6",
        "tslib": "^2.0.1",
        "zone.js": "~0.11.1"
    },
    "devDependencies": {
        "@angular-devkit/build-angular": "^0.901.12",
        "@angular/cli": "^9.1.12",
        "@angular/compiler-cli": "^9.1.12",
        "@angular/language-service": "~9.1.12",
        "@types/jasmine": "~3.5.14",
        "@types/jasminewd2": "~2.0.8",
        "@types/lodash": "^4.14.161",
        "codelyzer": "~6.0.0",
        "eslint": "~7.8.1",
        "jasmine-core": "~3.6.0",
        "jasmine-spec-reporter": "~5.0.2",
        "karma": "^5.2.2",
        "karma-chrome-launcher": "~3.1.0",
        "karma-coverage-istanbul-reporter": "~3.0.3",
        "karma-jasmine": "~4.0.1",
        "karma-jasmine-html-reporter": "^1.5.4",
        "protractor": "~7.0.0",
        "ts-node": "~9.0.0",
        "typescript": "~3.8.3"
    }
}

1. In tsconfig.json add: "angularCompilerOptions": { "enableIvy": true }

Your Environment

• NodeJS v12.13.0
• Operating System and version: Win 10 Pro 20H2

Workarounds

• Remove : "scripts: { "postinstall": "ngcc" } from package.json
• Add following parameters to postinstall: "postinstall": "ngcc --properties es2015 es5 browser module main --first-only --create-ivy-entry-points"

[manishjanky]

Please update to v2.0.0

let me know if you face issues

[manishjanky]

Let me have a look at this.