From 22d9f20dee4aa73aab81a9642edc98ee5fc20868 Mon Sep 17 00:00:00 2001
From: Ben Gotow <ben@foundry376.com>
Date: Tue, 13 Feb 2018 23:40:31 -0800
Subject: [PATCH] =?UTF-8?q?Composer=20perf:=20preload=20components=20to=20?=
 =?UTF-8?q?avoid=20parsing=20javascript=20on=20=E2=80=9Creply=E2=80=9D?=
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---
 app/src/global/mailspring-component-kit.es6 | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/app/src/global/mailspring-component-kit.es6 b/app/src/global/mailspring-component-kit.es6
index 1dc630bc84..3fe739be72 100644
--- a/app/src/global/mailspring-component-kit.es6
+++ b/app/src/global/mailspring-component-kit.es6
@@ -5,6 +5,24 @@
 // `require` files the first time they're called.
 module.exports = exports = {};
 
+// Because requiring files the first time they're used hurts performance, we
+// automatically load components slowly in the background using idle cycles.
+setTimeout(() => {
+  const remaining = Object.keys(module.exports);
+  const fn = deadline => {
+    let key = null;
+    let bogus = 0; // eslint-disable-line
+    while ((key = remaining.pop())) {
+      bogus += module.exports[key] ? 1 : 0;
+      if (deadline.timeRemaining() <= 0) {
+        window.requestIdleCallback(fn, { timeout: 5000 });
+        return;
+      }
+    }
+  };
+  window.requestIdleCallback(fn, { timeout: 5000 });
+}, 500);
+
 const resolveExport = requireValue => {
   return requireValue.default || requireValue;
 };