1 files changed, 47 insertions, 0 deletions
diff --git a/html/DOM_helpers.js b/html/DOM_helpers.js
index 88092e5..9e64956 100644
--- a/html/DOM_helpers.js
+++ b/html/DOM_helpers.js
@@ -85,3 +85,50 @@ function clone_template(template_id)
     return result_object;
 }
 #EXPORT clone_template
+
+function Showable(on_show_cb, on_hide_cb) {
+    this.shown = false;
+
+    /*
+     * Wrap the requested callback into one that only executes it if showable is
+     * not shown.
+     */
+    this.when_hidden = cb => {
+	const wrapped_cb = (...args) => {
+	    if (!this.shown)
+		return cb(...args);
+	}
+	return wrapped_cb;
+    }
+
+    this.show = () => {
+	if (this.shown)
+	    return false;
+
+	this.shown = true;
+
+	try {
+	    on_show_cb();
+	} catch(e) {
+	    console.error(e);
+	}
+
+	return true;
+    }
+
+    this.hide = () => {
+	if (!this.shown)
+	    return false;
+
+	this.shown = false;
+
+	try {
+	    on_hide_cb();
+	} catch(e) {
+	    console.error(e);
+	}
+
+	return true;
+    }
+}
+#EXPORT Showable