Refactored and fixed:

- Refactored, linted, fixed potential problems, enabled 'use strict'

Fixed:
- Added "Enable plugin synchronization" option
(Plugins and settings had been run always)

Implemented:
- Sync preset implemented.
- "Check integrity on saving" implemented.
- "Sanity check" implemented
It's mainly for debugging.

src/LogDisplayModal.ts

@@ -0,0 +1,37 @@
+import { App, Modal } from "obsidian";
+import { escapeStringToHTML } from "./utils";
+import ObsidianLiveSyncPlugin from "./main";
+
+export class LogDisplayModal extends Modal {
+    plugin: ObsidianLiveSyncPlugin;
+    logEl: HTMLDivElement;
+    constructor(app: App, plugin: ObsidianLiveSyncPlugin) {
+        super(app);
+        this.plugin = plugin;
+    }
+    updateLog() {
+        let msg = "";
+        for (const v of this.plugin.logMessage) {
+            msg += escapeStringToHTML(v) + "<br>";
+        }
+        this.logEl.innerHTML = msg;
+    }
+    onOpen() {
+        const { contentEl } = this;
+
+        contentEl.empty();
+        contentEl.createEl("h2", { text: "Sync Status" });
+        const div = contentEl.createDiv("");
+        div.addClass("op-scrollable");
+        div.addClass("op-pre");
+        this.logEl = div;
+        this.updateLog = this.updateLog.bind(this);
+        this.plugin.addLogHook = this.updateLog;
+        this.updateLog();
+    }
+    onClose() {
+        const { contentEl } = this;
+        contentEl.empty();
+        this.plugin.addLogHook = null;
+    }
+}