From c2cec80d0920cc9036d94dee337f4aa9fff34615 Mon Sep 17 00:00:00 2001
From: Nicky Kalu <nickykalu@microsoft.com>
Date: Fri, 23 Aug 2024 08:05:12 +0300
Subject: [PATCH] feat: Enable override to NPM_CONCURRENCY defaults through env
 variable (#972)

---
 README.md                                                  | 4 ++++
 change/beachball-3a1535e5-d3c6-4f91-a673-17f6e527edb3.json | 7 +++++++
 src/env.ts                                                 | 2 ++
 src/packageManager/listPackageVersions.ts                  | 2 +-
 4 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 change/beachball-3a1535e5-d3c6-4f91-a673-17f6e527edb3.json

diff --git a/README.md b/README.md
index d8a384b5a..b3d96441d 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,10 @@ show help message
 
 skips the prompts for publish
 
+## Overriding Concurrency
+
+In large monorepos, the Beachball sync process can be time-consuming due to the high number of packages. To optimize performance, you can override the default concurrency (typically set to 2 or 5) by setting the NPM_CONCURRENCY environment variable to a value that best suits your needs
+
 ## Examples
 
 ```
diff --git a/change/beachball-3a1535e5-d3c6-4f91-a673-17f6e527edb3.json b/change/beachball-3a1535e5-d3c6-4f91-a673-17f6e527edb3.json
new file mode 100644
index 000000000..54381ce2c
--- /dev/null
+++ b/change/beachball-3a1535e5-d3c6-4f91-a673-17f6e527edb3.json
@@ -0,0 +1,7 @@
+{
+  "type": "minor",
+  "comment": "override NPM_CONCURRENCY defaults through env variable",
+  "packageName": "beachball",
+  "email": "nickykalu@microsoft.com",
+  "dependentChangeType": "patch"
+}
diff --git a/src/env.ts b/src/env.ts
index 428b2534a..8606f7c12 100644
--- a/src/env.ts
+++ b/src/env.ts
@@ -17,4 +17,6 @@ export const env = Object.freeze({
   // These are borrowed from workspace-tools
   workspaceToolsGitDebug: !!process.env.GIT_DEBUG,
   workspaceToolsGitMaxBuffer: (process.env.GIT_MAX_BUFFER && parseInt(process.env.GIT_MAX_BUFFER, 10)) || undefined,
+  // Override default NPM_CONCURRENCY
+  npmConcurrency: (process.env.NPM_CONCURRENCY && parseInt(process.env.NPM_CONCURRENCY)) || undefined
 });
diff --git a/src/packageManager/listPackageVersions.ts b/src/packageManager/listPackageVersions.ts
index 2ebcd7323..5390180b7 100644
--- a/src/packageManager/listPackageVersions.ts
+++ b/src/packageManager/listPackageVersions.ts
@@ -18,7 +18,7 @@ export type NpmShowResult = PackageJson & {
 
 let packageVersionsCache: { [pkgName: string]: NpmShowResult | false } = {};
 
-const NPM_CONCURRENCY = env.isJest ? 2 : 5;
+const NPM_CONCURRENCY = env.npmConcurrency ?? (env.isJest ? 2 : 5);
 
 export function _clearPackageVersionsCache(): void {
   packageVersionsCache = {};