Electron 7 Development Environment

I am building an app with NodeJS and Electron 7. I am trying to write a shell.nix file for my development environment. However, I can’t figure out how to set up the Electron package: the most recent version of Electron in nixpkgs is version 6 (I need version 7).

I tried to copy electron_6 expression to the directory of my project (named it electron_7.nix). I changed the version to “7.1.2” and imported the package with callPackage ./electron_7.nix in shell.nix. However, when I enter the environment (nix-shell) and run electron --version it prints v6.0.1 and not v7.1.2.

I guess electron gets cached somehow because it also didn’t yell that hashes don’t match in fetchurl function calls.

How should I solve this issue?

Thanks in advance.

My shell.nix:

with import <nixpkgs> {};

  electron_7 = callPackage ./electron_7.nix {};
in mkShell {
  buildInputs = [

Ok, I actually just needed to manually update the sha256 hash for fetchurl. I used nix-prefetch-url to get the new hash.