To successfully enable the functionality, I made sure to specify the files attribute within the configuration file named tsconfig.app.json. These specified files are referenced in relation to the location of the tsconfig.app.json file.

"files": [
    "app.js",
    "styles.scss"
  ]

Following an upgrade from Angular 8 to Angular 9, I encountered complaints about environment.*.ts files that were listed in angular.json for various builds. Despite not running ng update, which would typically update tsconfig.json with certain configurations, I manually updated tsconfig.json as a workaround.

    "files": [
        "src/main.ts",
        "src/polyfills.ts"
    ],
    "include": [
        "src/**/*.d.ts"
    ]

Fortunately, this resolved the warnings for me.

Update on May 27, 2020:

I discovered that the previously mentioned block of code is no longer necessary with Angular 9.1.x in Visual Studio Professional 2019. Keeping it could lead to errors in spec test codes complaining about missing modules, even though everything appears to be functioning correctly during testing and building.

Below is my current tsconfig.json configuration:

{
    "compileOnSave": false,
    "compilerOptions": {
        "baseUrl": "./",
        "outDir": "./dist/out-tsc",
        "sourceMap": true,
        "declaration": false,
        "module": "es2020",
        "moduleResolution": "node",
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "target": "es2015",
        "typeRoots": [
            "node_modules/@types"
        ],
        "lib": [
            "es2018",
            "dom"
        ],
        "skipLibCheck": true
    }
}

Remarks:

As a note, my development targets are Google Chrome and Safari. If you plan to target other browsers, adjustments may be necessary.

Have you encountered issues with @angular-builders/custom-webpack?

I suddenly started receiving unfamiliar messages in my Angular 10 project. Even after adjusting the includes, the problem persisted.

Fortunately, I stumbled upon https://github.com/angular/angular/pull/36211.

This issue seems similar to what was mentioned here but related to ngtypecheck.ts files (not entirely certain about their purpose!)

WARNING in /home/circleci/ng/aio/src/main.ngtypecheck.ts is part of the TypeScript compilation but it's unused. Add only entry points to the 'files' or 'include' properties in your tsconfig.

In my case, it appears to be connected to @angular-builders/custom-webpack.

There was recently an open discussion regarding this at https://github.com/just-jeb/angular-builders/issues/781. Kudos to for bringing attention to this.

My solution was updating to v10.0.1, which resolved the issue for me. However, I recommend checking the aforementioned thread for any new updates.

"@angular-builders/custom-webpack": "10.0.1"    // current version

It may be obvious to some, but it's worth noting that you will receive a warning for any file you add that is not yet referenced or imported into another file. The significance of this will become apparent when you try to edit one of the files mentioned in the warning, only to find that Ivy does not automatically recompile after the edit. Once you import the module into a dependent file and begin using it, the warnings will disappear.

While the answers provided by others may be helpful, the root cause of my warnings was exactly what I have described in this post. It's important to mention that I did not have an include or files array in my tsconfig.json or tsconfig.app.json files, and the warnings ceased once I actually referenced the files elsewhere in my project.

Just updated to the latest Angular 9 and encountered some warnings. I found a solution by adding an array called "files" in my tsconfig.app.json without including the "src" path:

 "files": [
    "main.ts",
    "polyfills.ts"
  ],

Here is my complete tsconfig.app.json file after making the changes:

{
  "extends": "../tsconfig.json",
  "compilerOptions": {
    "outDir": "../out-tsc/app",
    "module": "es2015",
    "types": ["node"]
  },
  "files": [
    "main.ts",
    "polyfills.ts"
  ],
  "exclude": [
    "src/test.ts",
    "**/*.spec.ts"
  ]
}

February 8th, 2020

Creating an Ionic 5+ Angular 9+ application.

Please take note: refer to the include section for more information.

tsconfig.app.json

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./out-tsc/app",
    "types": []
  },
  "files": [
    "src/main.ts",
    "src/polyfills.ts"
  ],
  "include": [
    "src/**/*.d.ts"
  ],
  "exclude": [
    "src/**/*.spec.ts"
  ]
}

Include the zone-flags.ts file and ensure that no other files are included in the list.

"files": [
    "src/main.ts",
    "src/polyfills.ts",
    "src/zone-flags.ts"
  ]

tsconfig.app.json

 "exclude": [
    "src/**/*.spec.ts",
    "src/test.ts",
    "src/environments/environment.prod.ts"
  ]

This code snippet provides the solution to the problem.

Upon encountering the notifications in Angular 10, I found it rather unexpected considering that it was a recent application generated using the CLI without any modifications. The warnings surfaced during a production build for both test.ts and environments.prod.ts. One would assume that these files would be automatically excluded, but to my surprise, they were not.

The reality is that these files are unnecessary for TypeScript transpilation; there is no need to bundle and deliver the .js versions of them to the browser. Both test.ts and environments.prod.ts serve as tools for meeting build-time requirements in Angular applications. Therefore, they can be included in the exclude section of the tsconfig.app.json file or any relevant TypeScript configuration file within your app, as illustrated below:

"exclude": [
    "src/**/*.spec.ts",
    "src/test.ts",
    "src/environments/environment.prod.ts"
]

By incorporating these additions as mentioned above, the warning alerts will cease to appear.

To resolve the issue, consider removing the directory node_modules/.cli-ngcc that stores the Angular CLI cache data.

After trying out the previous proposed solutions, I found success.

Make sure to update your package.json file

"@angular-devkit/build-angular": "~0.1000.3" 

You can view all available versions here:

https://www.npmjs.com/package/@angular-devkit/build-angular?activeTab=versions

Check which version is compatible with your current angular/core version

For Angular 10, use version 0.1000.3 of @angular-devkit/build-angular

Arriving fashionably late.

Encountered an issue here

The file src/environments/environment.prod.ts is a part of TypeScript compilation process, but it seems to be unused.
To address this, I must include the configuration in my tsconfig.app.json file

To resolve this, I will add the following entries to my tsconfig.app.json file:

"files": ["src/main.ts", "src/polyfills.ts"],
"include": ["src/**/*.d.ts"],

When I made the switch to Angular 10, I encountered similar warnings. Upon running npm i, there were reports of version discrepancies for certain development dependencies. By updating these (npm i <package>@latest) and moving nodejs to version 12 (previously was on version 10), the warnings disappeared.

In my scenario, the following packages required updates:

• @angular-devkit/build-angular
• codelyzer

Interestingly, I found that the classes mentioned in the warning message were indeed being used in my situation. The issue, however, stemmed from the fact that when importing these classes, they had the extension ".js".

Consequently, this specific line triggered the warning "WARNING in src\app\user.service.ts is part of the TypeScript compilation but it's unused":

import { UserService } from './user.service.js';

The problem was easily resolved by simply removing the ".js" extension:

import { UserService } from './user.service';

After struggling with a persistent issue for months, my team and I finally identified the root cause of our problem: an overly broad configuration in our tsconfig.worker.json. Countless "part of the TypeScript compilation but it's unused" messages flooded our logs, with seemingly every ts file in the application being listed multiple times.

The original configuration looked like this:

"include": [
  "src/**/*.worker.ts"
]

To resolve the issue, we made a simple adjustment:

"files": [ ]   # no include or exclude block

It appears that our standard tsconfig.app.json's files entry points were sufficient for the TS compiler to transpile all the necessary *.worker.ts files based on main.ts and polyfills.ts references. The redundant references in tsconfig.webworker.ts seemed to be causing confusion, resulting in excessive warnings. It is possible that our webworker files (of which we have around 20) are needlessly importing unnecessary dependencies.

By implementing this tweak, we successfully eliminated the warning overload and significantly reduced our compilation time. What a relief!

After trying various approaches, I finally managed to find a solution for the issue at hand.

The challenge I faced involved upgrading an Angular 8.1 app to Angular 9.x while also utilizing Ionic.

To address this, ensure that you only have aot: true within the angular.json file.

In the src/polyfills.ts file, remember to import './zone-flags.ts' without the .ts extension.

For more guidance on upgrading from Ionic 4 to Ionic 5 with Angular, refer to this resource: https://medium.com/@grantbrits/upgrade-ionic-4-to-ionic-5-angular-76514079fb2aenter image description here

Take a look at your primary tsconfig.app.json configuration file.

https://i.stack.imgur.com/Vy9OE.png

Check if you have the following setup within it:

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./out-tsc/app",
    "types": []
  },
  "files": [
    "src/main.ts",
    "src/polyfills.ts"
  ],
  "include": [
    "src/**/*.d.ts"
  ]
}

It's likely that the issue stems from these specific lines.

Make sure to only include entry points in the files or include properties of your tsconfig.

If these lines exist in your tsconfig.app.json, consider removing them. This is likely causing the error :)

"exclude": [
    "src/test.ts",
    "**/*.spec.ts"
  ]

I hope this information can be beneficial to someone out there.

Thank you.

After upgrading my Angular 9 application to Angular 10, I encountered a similar problem. Fortunately, the issue was resolved by updating angular-devkit.

For me, the simpler solution was to remove the unnecessary files:

"exclude": ["data.ts", "**/*.backup.ts","samples/test.*.ts"]

In the situation I encountered, my tsconfig.json file was lacking the exclude directive for spec files. By adding the specific exclude rule in my tsconfig file as shown below, I was able to resolve the problem.

"exclude": [
"**/*.spec.ts",
"./node_modules/*"
],
 "files": [
"src/main.ts",
"src/polyfills.ts"
]

Essentially, the issue arises during runtime when the compiler verifies whether certain files are being imported or used in any way. If they are not, warnings are generated. If these warnings specifically pertain to environment.ts files, you have the option to exclude them in tsconfig.app.json like mentioned in the comments. However, if the warnings relate to components that are not being utilized anywhere, it is crucial to investigate why and determine if they can be safely removed.

I faced a similar issue as well. The problem stemmed from my angular.json file pointing to the incorrect tsConfig file. Instead of targeting tsconfig.app.json, it was referencing tsconfig.json.

To resolve this in angular.json:

"build": {
    "options": {
        "polyfills": "src/polyfills.ts",
        "tsConfig": "src/tsconfig.app.json"
    }
}

In tsconfig.app.json, I made sure to extend tsconfig.json and added the necessary 'files' and 'include' arrays to address the issue effectively.