From 94399bcbf3f2b2923b392fcc414b348b77f74206 Mon Sep 17 00:00:00 2001
From: Jamie Peabody <jpeabody@axway.com>
Date: Sat, 15 Jan 2022 20:01:37 +0000
Subject: [PATCH] chore: start of a webworker

---
 package.json       |  3 ++-
 src/diff-view.js   | 25 +++++++++++++++++++++----
 src/diff-worker.js |  8 ++++++++
 webpack.dev.js     |  5 +++++
 4 files changed, 36 insertions(+), 5 deletions(-)
 create mode 100644 src/diff-worker.js

diff --git a/package.json b/package.json
index 1fbf97e..574da24 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,8 @@
     "style-loader": "^2.0.0",
     "webpack": "^4.44.2",
     "webpack-cli": "^4.0.0",
-    "webpack-dev-server": "^3.11.0"
+    "webpack-dev-server": "^3.11.0",
+    "worker-loader": "^3.0.8"
   },
   "scripts": {
     "build": "npm run test && npm run build:dist",
diff --git a/src/diff-view.js b/src/diff-view.js
index 82d5a7e..80dd06a 100644
--- a/src/diff-view.js
+++ b/src/diff-view.js
@@ -993,10 +993,27 @@ CodeMirrorDiffView.prototype._diff = function() {
 	}
 	const lhs = this.editor.lhs.getValue();
 	const rhs = this.editor.rhs.getValue();
-	const comparison = new diff(lhs, rhs, this.settings);
-	this.changes = DiffParser(comparison.normal_form());
-	if (this.settings._debug.includes('change')) {
-		traceTimeEnd(' change#_diff');
+	/*
+	if (window.Worker) {
+		if (!this._diffWorker) {
+			trace(' change#_diff creating diff worker');
+			// this._diffWorker = new Worker('./diff-worker.js');
+			this._diffWorker = new Worker(new URL('./diff-worker.js', import.meta.url));
+			this._diffWorker.onchange = (ev) => {
+				this.changes = ev.data;
+				this._clear();
+				this._changed();
+			}
+		}
+		trace(' change#_diff starting worker');
+		this._diffWorker.postMessage({ lhs, rhs });
+	} else 
+	*/{
+		const comparison = new diff(lhs, rhs, this.settings);
+		this.changes = DiffParser(comparison.normal_form());
+		if (this.settings._debug.includes('change')) {
+			traceTimeEnd(' change#_diff');
+		}
 	}
 };
 
diff --git a/src/diff-worker.js b/src/diff-worker.js
new file mode 100644
index 0000000..e1e62b5
--- /dev/null
+++ b/src/diff-worker.js
@@ -0,0 +1,8 @@
+const diff = require('./diff');
+
+onmessage = function (ev) {
+	const { lhs, rhs } = ev;
+	const compare = new diff(lhs, rhs, this.settings);
+	const changes = DiffParser(compare.normal_form());
+	postMessage(changes);
+};
diff --git a/webpack.dev.js b/webpack.dev.js
index c9f2686..bb28bb8 100644
--- a/webpack.dev.js
+++ b/webpack.dev.js
@@ -23,6 +23,11 @@ module.exports = {
 			}, {
 				loader: 'css-loader'
 			}]
+		}, {
+			test: /worker\.js$/,
+			use: {
+				loader: 'worker-loader'
+			}
 		}]
 	},