How do I get around this “Subject incorrectly extends Observable” error in TypeScript 2.4 and RxJS 5.x?

Question

When I compile, I get the following compiler error in the RxJS declaration files:

node_modules/rxjs/Subject.d.ts(16,22): error TS2415: Class \'Subject

        

Answer 1

In your Subject class:

change this line:

lift<R>(operator: Operator<T, R>): Observable<T>;

to :

lift<R>(operator: Operator<T, R>): Observable<R>;

Answer 2

Today, faced this error and solved this pratically with the below three steps. So sharing the same with the hope, it will help others.

Step 1: In the package.json file change the entry as "rxjs": "5.4.2",

Step 2: Delete the node_modules folder from the project,which is present in the root directory

Step 3 : Now ,Right click the package.json file and click restore like as shown below:

Note : It will again create node_module folder with the new files, Now build the solution, hopefully you should not get any build error related to above problem.

Answer 3

I have made the below two changes in package.json file.

1) changed the rxjs version to 5.4.1 in dependencies section.

"dependencies": {
"rxjs": "5.4.1" }

2) changed the typescript version to 2.4.0 in devDependencies section.

"devDependencies": { "typescript": "2.4.0" }

I ran 'npm install' command after making the two changes and it worked.