net: move isLegalPort to internal/net

isLegalPort can be used in more places than just net.js. This change
moves it to a new internal net module in preparation for using it in
the dns module.

PR-URL: https://github.com/nodejs/node/pull/4882
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/test/parallel/test-net-internal.js b/test/parallel/test-net-internal.js
new file mode 100644
index 0000000000..b59b92d0fb
--- /dev/null
+++ b/test/parallel/test-net-internal.js
@@ -0,0 +1,15 @@
+'use strict';
+
+// Flags: --expose-internals
+
+require('../common');
+const assert = require('assert');
+const net = require('internal/net');
+
+assert.strictEqual(net.isLegalPort(''), false);
+assert.strictEqual(net.isLegalPort('0'), true);
+assert.strictEqual(net.isLegalPort(0), true);
+assert.strictEqual(net.isLegalPort(65536), false);
+assert.strictEqual(net.isLegalPort('65535'), true);
+assert.strictEqual(net.isLegalPort(undefined), false);
+assert.strictEqual(net.isLegalPort(null), true);