message: add default npm repo to codebase and always pass it as a param
diff: use error::Error;
  use std::process::{Command, Stdio};
  +pub const DEFAULT_NPM_REGISTRY: &'static str = "https://registry.npmjs.org/";
  +
  pub fn npm_pack(path: &str) -> Result<(), Error> {
  let pkg_file_path = format!("{}/pkg", path);
  let output = Command::new("npm")
  @@ -30,16 +32,15 @@ pub fn npm_publish(path: &str) -> Result<(), Error> {
  }
  pub fn npm_login(
  - registry: Option<String>,
  - scope: Option<String>,
  + registry: &String,
  + scope: &Option<String>,
  always_auth: bool,
  - auth_type: Option<String>,
  + auth_type: &Option<String>,
  ) -> Result<(), Error> {
  let mut args = String::new();
  - if let Some(registry) = registry {
  args.push_str(&format!("--registry={}", registry));
  - }
  +
  if let Some(scope) = scope {
  args.push_str(&format!(" --scope={}", scope));
  }
  @@ -61,7 +62,7 @@ pub fn npm_login(
  if !output.status.success() {
  let s = String::from_utf8_lossy(&output.stderr);
  - Error::cli("Registry user account login failed", s)
  + Error::cli(&format!("Login to registry {} failed", registry), s)
  } else {
  Ok(())
  }
  