TypeError: Cannot read property 'flags' of undefined

Question

After cloning a repo, npm install && ionic cordova build android --prod shows me following error.

TypeError: Cannot read property 'flags' of undefined
    at checkUnreachable (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:24905:31)
    at bindChildrenWorker (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:23111:17)
    at bindChildren (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:23055:17)
    at bind (F:\Works\Projects\ionic-bokfinder\node_modules\typescript\lib\typescript.js:24319:21)
    at bindSourceFile

I am sure it worked well without any problems before. Here are my system information and package.json.

System:

    Node : v8.10.0
    npm  : 5.6.0
    OS   : Windows 10

Package.json:

"dependencies": {
    "@angular/common": "5.0.3",
    "@angular/compiler": "5.0.3",
    "@angular/compiler-cli": "5.0.3",
    "@angular/core": "5.0.3",
    "@angular/forms": "5.0.3",
    "@angular/http": "5.0.3",
    "@angular/platform-browser": "5.0.3",
    "@angular/platform-browser-dynamic": "5.0.3",
    "@ionic-native/core": "^4.5.2",
    "@ionic-native/facebook": "^4.5.2",
    "@ionic-native/firebase": "^4.5.2",
    "@ionic-native/in-app-browser": "^4.5.2",
    "@ionic-native/in-app-purchase": "^4.5.2",
    "@ionic-native/intercom": "^4.5.2",
    "@ionic-native/social-sharing": "^4.5.2",
    "@ionic-native/splash-screen": "4.4.0",
    "@ionic-native/status-bar": "4.4.0",
    "@ionic/storage": "2.1.3",
    "angularfire2": "^5.0.0-rc.6",
    "firebase": "^4.12.0",
    "ionic-angular": "3.9.2",
    "ionicons": "3.0.0",
    "raven-js": "^3.17.0",
    "rxjs": "5.5.2",
    "sw-toolbox": "3.6.0",
    "zone.js": "^0.8.18"
  },
  "devDependencies": {
    "@angular/cli": "^1.7.3",
    "@ionic/app-scripts": "^3.1.8",
    "@types/jasmine": "2.8.4",
    "@types/node": "9.3.0",
    "html-loader": "0.5.5",
    "istanbul-instrumenter-loader": "3.0.0",
    "jasmine": "2.9.0",
    "jasmine-spec-reporter": "4.2.1",
    "karma": "2.0.0",
    "karma-chrome-launcher": "2.2.0",
    "karma-coverage-istanbul-reporter": "1.3.3",
    "karma-jasmine": "1.1.1",
    "karma-jasmine-html-reporter": "0.2.2",
    "karma-sourcemap-loader": "0.3.7",
    "karma-webpack": "2.0.9",
    "protractor": "5.2.2",
    "ts-loader": "3.2.0",
    "ts-node": "4.1.0",
    "tslint": "5.9.1",
    "typescript": "2.4.2"
  },

I guess this problem is related with @ionic/app-scripts issue.

Answer 1

Removing @angular/cli should work for you

if not, change Typescript version to ~2.6.2.

@angular/cli 1.7.3 works with Typescript ~2.6.2 only.

Answer 2

Installing angular 9.0.0 solved the problem for me

npm install @angular/[email protected] -g

it was breaking for angular 9.1.5

Answer 3

I'm using angular 5 and ionic v3. For me work these changes:

"@types/node": "^9.6.55",
"typescript": "3.7.4",
"@ionic/app-scripts": "3.2.3",

If your are using @angular/cli or @angular-devkit, in my case I had to remove it in order to build with --prod tag properly.

Be sure also to remove your node_modules and do npm cache clean -f, then npm i (maybe will be good also remove your package-lock.json)