From a9681ee7eb52e6c7ab665bf7cb3a892d524f3c4e Mon Sep 17 00:00:00 2001
From: John Factotum <50942278+johnfactotum@users.noreply.github.com>
Date: Fri, 19 May 2023 23:30:22 +0800
Subject: [PATCH] Add event and properties for history navigation availability

---
 view.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/view.js b/view.js
index 1a8adc3..3746ee1 100644
--- a/view.js
+++ b/view.js
@@ -10,6 +10,7 @@ class History extends EventTarget {
         if (last === x || last?.fraction && last.fraction === x.fraction) return
         this.#arr[++this.#index] = x
         this.#arr.length = this.#index + 1
+        this.dispatchEvent(new Event('index-change'))
     }
     replaceState(x) {
         const index = this.#index
@@ -21,6 +22,7 @@ class History extends EventTarget {
         const detail = { state: this.#arr[index - 1] }
         this.#index = index - 1
         this.dispatchEvent(new CustomEvent('popstate', { detail }))
+        this.dispatchEvent(new Event('index-change'))
     }
     forward() {
         const index = this.#index
@@ -28,6 +30,13 @@ class History extends EventTarget {
         const detail = { state: this.#arr[index + 1] }
         this.#index = index + 1
         this.dispatchEvent(new CustomEvent('popstate', { detail }))
+        this.dispatchEvent(new Event('index-change'))
+    }
+    get canGoBack() {
+        return this.#index > 0
+    }
+    get canGoForward() {
+        return this.#index < this.#arr.length - 1
     }
 }