aspnetcore: missing blazor.web.js

[corngood]

my build keeps failing due to this:
CSC : error CS1566: Error reading resource '_framework/blazor.web.js' -- 'Could not find a part of the path '/home/janvorli/git/dotnet/src/aspnetcore/src/Components/Web.JS/dist/Release/blazor.web.js'.' [/home/janvorli/git/dotnet/src/aspnetcore/src/Components/Endpoints/src/Microsoft.AspNetCore.Components.Endpoints.csproj] [/home/janvorli/git/dotnet/repo-projects/aspnetcore.proj]

I've tried several times, even with git clean -xdf in between. Any idea what is wrong?

Originally posted by @janvorli in #4007 (comment)

I'm also getting this in 9.0.0-preview.2, where it's preceded by this warning:

src/aspnetcore/src/Components/Endpoints/src/Microsoft.AspNetCore.Components.Endpoints.csproj(67,5): warning : 'src/aspnetcore/src/Components/Endpoints/src/../../Web.JS/dist/Release/blazor.web.js' does not exist. Ensure the JS assets have been build by running 'npm run build' from the repository root. [repo-projects/aspnetcore.proj]

@janvorli, I wanted to ask if you were able to fix this, but it seems to be a bit of-topic in #4007.

[corngood]

Ah, I see:

warning: Building of NodeJS projects is disabled since node is not detected on Path and no BuildNodeJs or NoBuildNodeJs setting is set explicitly.
warning: Some managed projects depend on NodeJS projects. Building NodeJS is disabled so the managed projects will fallback to using the output from previous builds. The output may not be correct or up to date.

Also based on this I found #3924, so I'm going to close this as a duplicate.