[Fixed] Invalid module name in augmentation — error while using map option for RxJs – Rxjs

The Problem:

An error, "Invalid module name in augmentation — error while using map option for RxJs," is being received in map.d.ts, due to which the intellisense is not complete.

The Solutions:

Solution 1: Moving imports inside module

To resolve the error, move all the imports into the declare module "moduleName" {} block in your .d.ts file. This ensures that the module name is valid and recognized by the compiler.

Solution 2: Upgrade RxJS to ^5.0.0 and modify imports

1. Ensure that your RxJS version in package.json is greater than or equal to "^5.0.0."

2. Add the following @import statement before the Observable declaration:

   import {Observable} from 'rxjs';
   

3. Modify the declare module statement to:

   declare module 'rxjs' {
       interface Observable<T> {
           // Additional methods and properties
       }
   }
   

This updates the reference to the Observable type and allows for proper augmentation with additional methods or properties in the map operator.

Solution 3: Update Language Service Manually

The error you’re encountering indicates that your typescript language service is outdated. The language service in Webpack 2.2.0 has a version of TypeScript that doesn’t support module augmentation introduced in TypeScript 1.8.

To resolve this issue, you can manually update the language service to the latest version by following these steps:

1. Install the latest version of TypeScript:

npm install -g typescript

2. Create a new TypeScript configuration file (tsconfig.json) at the root of your project:

{
  "module": "commonjs",
  "target": "es5"
}

3. Add the following line to your webpack.config.js file:

module.exports = {
  // ... other webpack config options
  module: {
    rules: [
      {
        test: /\.ts$/,
        loader: 'ts-loader',
        options: {
          transpileOnly: true,
          experimentalWatchApi: true
        }
      }
    ]
  }
};

4. Restart your webpack development server or run the build command again.

5. If the issue persists, try restarting your computer.

Once you’ve updated the language service, you should no longer receive the error message.