Is there simpler way to extract string from Nix string?

nixeval.md

function nixeval { eval echo -en "$(nix-instantiate --eval --strict "$@" | sed 's/${/\\${/g')"; }

Evaluate Nix expression and remove quotes from resulting expresssion:

$ nixeval -E 'builtins.toJSON __nixPath' | jq
[             
  {
    "path": "/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs",
    "prefix": "nixpkgs"
  },
  {
    "path": "/etc/nixos/configuration.nix",
    "prefix": "nixos-config"
  },
  {
    "path": "/nix/var/nix/profiles/per-user/root/channels",
    "prefix": ""
  },
  {
    "path": "/nix/store/jckpxyik29cvxyxafhlmi65w8xr3szkd-nix-1.11.11/share/nix/corepkgs",
    "prefix": "nix"
  }
]

Thanks, @edolstra

$ nix eval -f $(nix-build -E 'with import <nixpkgs>{}; writeText "example.nix" "builtins.toJSON __nixPath"') --raw | jq
[
  {
    "path": "/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs",
    "prefix": "nixpkgs"
  },
  {
    "path": "/etc/nixos/configuration.nix",
    "prefix": "nixos-config"
  },
  {
    "path": "/nix/var/nix/profiles/per-user/root/channels",
    "prefix": ""
  },
  {
    "path": "/nix/store/jbxvhbwzafs4w4di45kwic7rhf3mwdwk-nix-1.12pre5511_c94f3d55/share/nix/corepkgs",
    "prefix": "nix"
  }
]