From 548ff41467d60bb649ad2d9b31001f60825eb0e9 Mon Sep 17 00:00:00 2001
From: Bryan Ashby <bryan@l33t.codes>
Date: Thu, 1 Feb 2018 20:29:26 -0700
Subject: [PATCH] Conceptual MenuItem caching - WIP for testing, will impl. in
 others if it seems good

---
 core/menu_view.js          | 13 +++++++++++++
 core/vertical_menu_view.js | 11 ++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/core/menu_view.js b/core/menu_view.js
index f15491cf..dc2f5c81 100644
--- a/core/menu_view.js
+++ b/core/menu_view.js
@@ -29,6 +29,8 @@ function MenuView(options) {
 		this.items = [];
 	}
 
+	this.renderCache = {};
+
 	this.caseInsensitiveHotKeys = miscUtil.valueWithDefault(options.caseInsensitiveHotKeys, true);
 
 	this.setHotKeys(options.hotKeys);
@@ -65,6 +67,7 @@ util.inherits(MenuView, View);
 MenuView.prototype.setItems = function(items) {
 	if(Array.isArray(items)) {
 		this.sorted = false;
+		this.renderCache = {};
 
 		//
 		//	Items can be an array of strings or an array of objects.
@@ -98,6 +101,16 @@ MenuView.prototype.setItems = function(items) {
 	}
 };
 
+MenuView.prototype.getRenderCacheItem = function(index, focusItem = false) {
+	const item = this.renderCache[index];
+	return item && item[focusItem ? 'focus' : 'standard'];
+};
+
+MenuView.prototype.setRenderCacheItem = function(index, rendered, focusItem = false) {
+	this.renderCache[index] = this.renderCache[index] || {};
+	this.renderCache[index][focusItem ? 'focus' : 'standard'] = rendered;
+};
+
 MenuView.prototype.setSort = function(sort) {
 	if(this.sorted || !Array.isArray(this.items) || 0 === this.items.length) {
 		return;
diff --git a/core/vertical_menu_view.js b/core/vertical_menu_view.js
index 423ffc00..57570e16 100644
--- a/core/vertical_menu_view.js
+++ b/core/vertical_menu_view.js
@@ -64,6 +64,11 @@ function VerticalMenuView(options) {
 			return;
 		}
 
+		const cached = this.getRenderCacheItem(index, item.focused);
+		if(cached) {
+			return self.client.term.write(`${ansi.goto(item.row, self.position.col)}${cached}`);
+		}
+
 		let text;
 		let sgr;
 		if(item.focused && self.hasFocusItems()) {
@@ -78,9 +83,9 @@ function VerticalMenuView(options) {
 			sgr = (index === self.focusedItemIndex ? self.getFocusSGR() : self.getSGR());
 		}
 
-		self.client.term.write(
-			`${ansi.goto(item.row, self.position.col)}${sgr}${strUtil.pad(text, this.dimens.width, this.fillChar, this.justify)}`
-		);
+		text = `${sgr}${strUtil.pad(text, this.dimens.width, this.fillChar, this.justify)}`;
+		self.client.term.write(`${ansi.goto(item.row, self.position.col)}${text}`);
+		this.setRenderCacheItem(index, text, item.focused);
 	};
 }