From a9fcbbd9408fb51f7fa561add27c0dc62712ada6 Mon Sep 17 00:00:00 2001
From: Joel Denning <joeldenning@gmail.com>
Date: Mon, 28 Oct 2019 19:17:35 -0600
Subject: [PATCH] Supporting narn global commands (forces yarn). Resolves #5.

---
 bin/narn.js         |  2 +-
 lib/narn-lib.js     | 25 +++++++++++++++----------
 test/global.test.js | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 11 deletions(-)
 create mode 100644 test/global.test.js

diff --git a/bin/narn.js b/bin/narn.js
index 777b065..b8b3f41 100755
--- a/bin/narn.js
+++ b/bin/narn.js
@@ -9,8 +9,8 @@ const narnPackageJson = JSON.parse(
 );
 
 async function runPackageManager() {
-  const isYarn = await detectYarn();
   const narnArgs = process.argv.slice(2);
+  const isYarn = await detectYarn(narnArgs);
 
   const command = isYarn ? "yarn" : "npm";
   const commandArgs = isYarn ? getYarnArgs(narnArgs) : getNpmArgs(narnArgs);
diff --git a/lib/narn-lib.js b/lib/narn-lib.js
index f75624d..edf0966 100644
--- a/lib/narn-lib.js
+++ b/lib/narn-lib.js
@@ -3,16 +3,21 @@ const path = require("path");
 const minimist = require("minimist");
 const validateNpmPackageName = require("validate-npm-package-name");
 
-exports.detectYarn = function detectYarn() {
-  return new Promise((resolve, reject) => {
-    fs.access(
-      path.resolve(process.cwd(), "package-lock.json"),
-      fs.constants.F_OK,
-      noPackageLock => {
-        resolve(Boolean(noPackageLock));
-      }
-    );
-  });
+exports.detectYarn = function detectYarn(args) {
+  if (args && args.length > 0 && args[0] === "global") {
+    // all global commands go through yarn
+    return Promise.resolve(true);
+  } else {
+    return new Promise((resolve, reject) => {
+      fs.access(
+        path.resolve(process.cwd(), "package-lock.json"),
+        fs.constants.F_OK,
+        noPackageLock => {
+          resolve(Boolean(noPackageLock));
+        }
+      );
+    });
+  }
 };
 
 exports.getYarnArgs = narnArgs => narnArgs;
diff --git a/test/global.test.js b/test/global.test.js
new file mode 100644
index 0000000..7fae246
--- /dev/null
+++ b/test/global.test.js
@@ -0,0 +1,33 @@
+const { detectYarn } = require("../lib/narn-lib");
+const fs = require("fs");
+
+jest.mock("fs", () => ({
+  access: jest.fn(),
+  constants: {
+    F_OK: 1
+  }
+}));
+
+describe("narn global commands", () => {
+  beforeEach(() => {
+    fs.access.mockReset();
+  });
+
+  it("supports installing global packages", async () => {
+    const isYarn = await detectYarn(["global", "add", "lodash@1.0.0"]);
+    expect(isYarn).toBe(true);
+  });
+
+  it("supports uninstalling global packages", async () => {
+    const isYarn = await detectYarn(["global", "remove", "lodash"]);
+    expect(isYarn).toBe(true);
+  });
+
+  it("doesn't think everything is global", async () => {
+    fs.access.mockImplementationOnce((path, mode, errBack) => {
+      errBack(false);
+    });
+    const isYarn = await detectYarn(["add", "lodash@1.0.0"]);
+    expect(isYarn).toBe(false);
+  });
+});