How do I get around this "Subject incorrectly extends Observable" error in TypeScript 2.4 and RxJS 5.x?
Solution
RxJS 5.4.2 should now work perfectly with TypeScript 2.4.1. Simply upgrade to 5.4.2+ if possible.
npm install --save rxjs@^5.4.2
Then try restarting your editor and/or recompile if you don't see an immediate change.
If not, the below solution should work.
Why it's happening
TypeScript 2.4 has a strictness change, and Subject<T>
isn't lifting to the correct Observable
. The signature really should have been
<R>(operator: Operator<T, R>) => Observable<R>
This will be fixed in RxJS 6.
Alternative Solution
Newer versions of RxJS will have this fixed, but as a temporary workaround, you can use the noStrictGenericChecks
compiler option.
In tsconfig.json
, put it in "compilerOptions"
and set it to true
.
{
"compilerOptions": {
"noStrictGenericChecks": true
}
}
On the command line it's --noStrictGenericChecks
.
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.
Add
"noStrictGenericChecks": true
in tsconfig.json file