fix(list): Do not emit empty stdout when there are no results

lerna · Feb 14, 2019 · ba54439 · ba54439
1 parent 6ff53d6
commit ba54439
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/commands/list/__tests__/list-command.test.js b/commands/list/__tests__/list-command.test.js
@@ -2,6 +2,7 @@
 
 // mocked modules
 const output = require("@lerna/output");
+const collectUpdates = require("@lerna/collect-updates");
 
 // helpers
 const initFixture = require("@lerna-test/init-fixture")(__dirname);
@@ -130,6 +131,18 @@ __TEST_ROOTDIR__/packages/package-5:package-5:1.0.0:PRIVATE
       await lernaLs(testDir)("--no-private");
       expect(output.logged()).not.toMatch("package-5 v1.0.0 (private)");
     });
+
+    it("does not emit empty stdout", async () => {
+      collectUpdates.setUpdated(testDir);
+      await lernaLs(testDir)("--since", "deadbeef");
+      expect(output).not.toHaveBeenCalled();
+      expect(collectUpdates).toHaveBeenLastCalledWith(
+        expect.any(Array),
+        expect.any(Map),
+        expect.any(Object),
+        expect.objectContaining({ since: "deadbeef" })
+      );
+    });
   });
 
   describe("in a repo with packages outside of packages/", () => {

diff --git a/commands/list/index.js b/commands/list/index.js
@@ -28,7 +28,10 @@ class ListCommand extends Command {
   }
 
   execute() {
-    output(this.result.text);
+    // piping to `wc -l` should not yield 1 when no packages matched
+    if (this.result.count) {
+      output(this.result.text);
+    }
 
     this.logger.success(
       "found",