From 65a2794c1d9c316cc8c53c6fd08872dd94af584c Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <kittens@users.noreply.github.com>
Date: Thu, 3 Nov 2016 11:46:34 +0000
Subject: [PATCH] Add name lookups to ls command - fixes #1599 (#1643)

---
 src/cli/commands/ls.js | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/cli/commands/ls.js b/src/cli/commands/ls.js
index bb590bde35..f2174cce4a 100644
--- a/src/cli/commands/ls.js
+++ b/src/cli/commands/ls.js
@@ -5,13 +5,13 @@ import type Config from '../../config.js';
 import type PackageResolver from '../../package-resolver.js';
 import type PackageLinker from '../../package-linker.js';
 import type {Trees} from '../../reporters/types.js';
+import {MessageError} from '../../errors.js';
 import {Install} from './install.js';
 import Lockfile from '../../lockfile/wrapper.js';
 
 const invariant = require('invariant');
 
 export const requireLockfile = true;
-export const noArguments = true;
 
 function buildCount(trees: ?Trees): number {
   if (!trees || !trees.length) {
@@ -136,6 +136,31 @@ export async function run(
   const [depRequests, patterns] = await install.fetchRequestFromCwd();
   await install.resolver.init(depRequests, install.flags.flat);
 
+  let filteredPatterns: Array<string> = [];
+
+  if (args.length) {
+    const matchedArgs: Array<string> = [];
+
+    for (const pattern of patterns) {
+      const pkg = install.resolver.getStrictResolvedPattern(pattern);
+
+      // ignore patterns if their package names have been specified in arguments
+      if (args.indexOf(pkg.name) >= 0) {
+        matchedArgs.push(pkg.name);
+        filteredPatterns.push(pattern);
+      }
+    }
+
+    // throw an error if any package names were passed to filter that don't exist
+    for (const arg of args) {
+      if (matchedArgs.indexOf(arg) < 0) {
+        throw new MessageError(reporter.lang('unknownPackage', arg));
+      }
+    }
+  } else {
+    filteredPatterns = patterns;
+  }
+
   const {trees} = await buildTree(install.resolver, install.linker, patterns);
   reporter.tree('ls', trees);
 }