I encountered an error in my Angular 8 App and despite trying various solutions, including the accepted answer, I couldn't resolve it. Looking back at an Angular 6 App that compiled successfully, I discovered that I could bypass the library check by adding

"skipLibCheck": true

to the tsconfig.json file. Since my App was functioning without issues, I opted for this approach. Below is the updated configuration of my tsconfig.json file

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

Following this configuration update, no more errors occurred. Please Note: While the error was not fully resolved, it allowed me to bypass the issue temporarily. As my App is functioning as intended, I consider this error insignificant for now.

It appears that the issue may lie within your inclusion settings:

"include": [
    "app/**/*.ts",
    "app/**/*.tsx",
    "test/**/*.ts",
    "test/**/*.tsx",
    "node_modules/@types/**/*.d.ts",
    "./types/**/*.d.ts"
  ]

Typically, there is no need to explicitly include *.d.ts files, especially those from external libraries or node modules.

By specifying "node_modules/@types/**/*.d.ts" in your tsconfig file, you are overriding the default exclusion of everything under "node_modules", causing tsc to attempt to include them even though they are already declared.

For more information on configuring the "typeRoots", "files", and "include"/"exclude" options in your tsconfig.json, refer to the Typescript documentation here.

It turned out that I encountered an issue due to the presence of a node_modules folder in a parent directory of my project. The structure looked somewhat like this:

node_modules
my-project
- node_modules

The problem arose because the node_modules directory contained an outdated version of @types/node. Interestingly, the solution did not involve updating @types/node, but rather removing those unnecessary node_modules as they were not being utilized.

If you do require a parent directory node_modules with distinct types, you can specify the typeRoots as follows:

{
  "compilerOptions": {
    "module": "esnext",
    "target": "es6",
    "declaration": true,
    "outDir": "./dist",
    "typeRoots": ["./node_modules/@types/"]
  },
  "include": [
    "src/**/*"
  ]
}

This configuration ensures that the types from the parent node_modules are not considered during compilation. For further details, refer to: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html#types-typeroots-and-types

By default, all visible "@types" packages are included in the compilation process. Packages within node_modules/@types of any enclosing folder are deemed visible; specifically referring to packages within ./node_modules/@types/, ../node_modules/@types/, ../../node_modules/@types/, and so forth.

According to @Muhammad bin Yusrat's suggestion, make sure to run npm i @types/node@latest instead of npm i @types/node if you recently updated Angular to version 9. This solution worked for me personally.

Additionally, running ionic serve helped resolve another Ionic 5 console error related to 'refused to load image 'http:localhost:8100/favicon.ico' because it violates the following Content Security Policy' (see below).

https://i.sstatic.net/h0SBV.png

Another issue with 'IteratorResult' was caused by a "Spread Types" Error. For more insights on this, check out this link: Typescript: Spread types may only be created from object types. Essentially, if you have used a spread operator in your code like this

return { id: doc.payload.id, ...doc.payload.data() };

, you need to modify it to this

return { id: doc.payload.id, ...doc.payload.data() as {} };

by adding as {}

To fix the problem, include skipLibCheck: true in the compilerOptions section of the tsconfig.json file.

Implementing this solution successfully resolved the issue. For more information, refer to this resource

After uninstalling types/node with the command:

sudo npm remove @types/node

I then reinstalled it using the following command, which successfully resolved the issue for me.

sudo npm i @types/node

To enhance the typings in your Angular project, simply update the @types/node package in the devDependencies section:

 npm install --save-dev @types/node

It is important to note that no alterations should be made within the node_modules directory.

Sharing this solution may benefit others.

Facing a similar challenge while updating Angular from versions 8.2.11 to 9.1.13, I successfully resolved it by following these steps:

1. Delete the node_modules folder and package-lock.json file
2. Reinstall the dependencies using npm install

My issue was resolved by modifying the package.json file with the following changes:

"devDependencies": {
  "@angular-devkit/build-angular": "^15.2.0",
  "@angular/cli": "^15.2.7",
  "@angular/compiler-cli": "^15.2.8",
  "@types/jasmine": "~4.3.1",
  "@types/jasminewd2": "~2.0.10",
  "@types/node": "^18.7.11",
  "jasmine-core": "~4.6.0",
  "karma": "~6.4.2",
  "karma-chrome-launcher": "~3.2.0",
  "karma-coverage": "~2.2.0",
  "karma-jasmine": "~5.1.0",
  "karma-jasmine-html-reporter": "^2.0.0",
  "typescript": "~4.9.5"
},