fix(add): Allow --registry option

commands/add/README.md

@@ -33,6 +33,10 @@ $ lerna add --exact
 
 Add the new package with an exact version (e.g., `1.0.1`) rather than the default `^` semver range (e.g., `^1.0.1`).
 
+### `--registry <url>`
+
+Use a custom registry to install the targeted package.
+
 ## Examples
 
 ```sh

commands/add/__tests__/add-command.test.js

@@ -187,6 +187,23 @@ describe("AddCommand", () => {
     expect(await readPkg(testDir, "packages/package-1")).toDependOn("tiny-tarball", "1.0.0", { exact: true });
   });
 
+  it("accepts --registry option", async () => {
+    const testDir = await initFixture("basic");
+
+    try {
+      await lernaAdd(testDir)(
+        "@my-own/private-idaho",
+        "--registry",
+        "http://registry.cuckoo-banana-pants.com/"
+      );
+    } catch (err) {
+      // obviously this registry doesn't exist, thus it will always error
+      expect(err.message).toMatch("ENOTFOUND");
+    }
+
+    expect.assertions(1);
+  });
+
   it("should bootstrap changed packages", async () => {
     const testDir = await initFixture("basic");
 

commands/add/command.js

@@ -32,6 +32,12 @@ exports.builder = yargs => {
         alias: "exact",
         describe: "Save version exactly",
       },
+      registry: {
+        group: "Command Options:",
+        describe: "Use the specified registry for all npm client operations.",
+        type: "string",
+        requiresArg: true,
+      },
     })
     .example(
       "$0 add module-1 packages/prefix-*",