Can't install npm from bullseye-backports

[Grégory Pakosz <gregory.pakosz+debian@gmail.com>]

Hello,

I tried to install npm from bullseye-backports but nodejs dependency
can't be satisfied.

Can someone please have a look?

Here's what I tried, happy to do more tests:

---
root@bullseye:~# apt install -t bullseye-backports npm
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 npm : Depends: nodejs:any (>= 10) but it is not installable
       Recommends: node-tap but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

---
root@bullseye:~# apt-cache policy
Package files:
 100 /var/lib/dpkg/status
     release a=now
 100 http://deb.debian.org/debian bullseye-backports/main amd64 Packages
     release o=Debian
Backports,a=bullseye-backports,n=bullseye-backports,l=Debian
Backports,c=main,b=amd64
     origin deb.debian.org
 500 http://deb.debian.org/debian bullseye-updates/main amd64 Packages
     release v=11-updates,o=Debian,a=stable-updates,n=bullseye-updates,l=Debian,c=main,b=amd64
     origin deb.debian.org
 500 http://security.debian.org/debian-security bullseye-security/main
amd64 Packages
     release v=11,o=Debian,a=stable-security,n=bullseye-security,l=Debian-Security,c=main,b=amd64
     origin security.debian.org
 500 http://deb.debian.org/debian bullseye/main amd64 Packages
     release v=11.2,o=Debian,a=stable,n=bullseye,l=Debian,c=main,b=amd64
     origin deb.debian.org
Pinned packages:

---
root@bullseye:~# apt-cache policy npm
npm:
  Installed: 7.5.2+ds-2
  Candidate: 7.5.2+ds-2
  Version table:
     8.3.1~ds-1~bpo11+1 100
        100 http://deb.debian.org/debian bullseye-backports/main amd64 Packages
 *** 7.5.2+ds-2 500
        500 http://deb.debian.org/debian bullseye/main amd64 Packages
        100 /var/lib/dpkg/status

---
root@bullseye:~# apt-cache policy nodejs
nodejs:
  Installed: 12.22.5~dfsg-2~11u1
  Candidate: 12.22.5~dfsg-2~11u1
  Version table:
 *** 12.22.5~dfsg-2~11u1 500
        500 http://deb.debian.org/debian bullseye/main amd64 Packages
        500 http://security.debian.org/debian-security
bullseye-security/main amd64 Packages
        100 /var/lib/dpkg/status


Thank you,
Gregory