feat: add --replace-registry-host=<npmjs|always|never> (#4860)

feat: add --replace-registry-host=<npmjs|always|never>|<hostname>

2 files changed, 12 insertions, 2 deletions

diff --git a/workspaces/arborist/lib/arborist/index.js b/workspaces/arborist/lib/arborist/index.js
index cb6ef1e0c..9564f7648 100644
--- a/workspaces/arborist/lib/arborist/index.js
+++ b/workspaces/arborist/lib/arborist/index.js
@@ -74,8 +74,12 @@ class Arborist extends Base {
       cache: options.cache || `${homedir()}/.npm/_cacache`,
       packumentCache: options.packumentCache || new Map(),
       workspacesEnabled: options.workspacesEnabled !== false,
+      replaceRegistryHost: options.replaceRegistryHost,
       lockfileVersion: lockfileVersion(options.lockfileVersion),
     }
+    this.replaceRegistryHost = this.options.replaceRegistryHost =
+      (!this.options.replaceRegistryHost || this.options.replaceRegistryHost === 'npmjs') ?
+        'registry.npmjs.org' : this.options.replaceRegistryHost
 
     this[_workspacesEnabled] = this.options.workspacesEnabled
 
diff --git a/workspaces/arborist/lib/arborist/reify.js b/workspaces/arborist/lib/arborist/reify.js
index 4f1061e4a..7663a3a34 100644
--- a/workspaces/arborist/lib/arborist/reify.js
+++ b/workspaces/arborist/lib/arborist/reify.js
@@ -712,13 +712,19 @@ module.exports = cls => class Reifier extends cls {
   [_registryResolved] (resolved) {
     // the default registry url is a magic value meaning "the currently
     // configured registry".
+    // `resolved` must never be falsey.
     //
     // XXX: use a magic string that isn't also a valid value, like
     // ${REGISTRY} or something.  This has to be threaded through the
     // Shrinkwrap and Node classes carefully, so for now, just treat
     // the default reg as the magical animal that it has been.
-    return resolved && resolved
-      .replace(/^https?:\/\/registry\.npmjs\.org\//, this.registry)
+    const resolvedURL = new URL(resolved)
+    if ((this.options.replaceRegistryHost === resolvedURL.hostname)
+      || this.options.replaceRegistryHost === 'always') {
+      // this.registry always has a trailing slash
+      resolved = `${this.registry.slice(0, -1)}${resolvedURL.pathname}${resolvedURL.searchParams}`
+    }
+    return resolved
   }
 
   // bundles are *sort of* like shrinkwraps, in that the branch is defined