timeZone property sets timezone for display. Value is always expected to be UTC (in- and outbound)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@tp/tp-date-input",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "",
   "main": "tp-date-input.js",
   "scripts": {
@@ -13,8 +13,7 @@
   "author": "trading_peter",
   "license": "Apache-2.0",
   "dependencies": {
-    "date-fns": "^2.0.0",
+    "luxon": "^3.0.0",
-    "date-fns-tz": "^2.0.0",
     "lit": "^3.0.0"
   }
 }

tp-date-input.js

@@ -291,17 +291,27 @@ class TpDateInput extends EventHelpers(ControlState(FormElement(LitElement))) {
       return;
     }
 
-    const date = parse(i0 + '-' + i1 + '-' + i2, this._inputAssign.join('-'), new Date());
+    // Convert luxon format to match input assignment
+    const luxonFormat = this._inputAssign.map(part => {
+      switch (part) {
+        case 'MM': return 'LL';
+        case 'dd': return 'dd';
+        case 'y': return 'yyyy';
+        default: return part;
+      }
+    }).join('-');
+
+    // Parse the date in the specified timezone (or local if not set).
+    // This interprets the entered values as being in that timezone.
+    const dt = DateTime.fromFormat(i0 + '-' + i1 + '-' + i2, luxonFormat, { zone: this.timeZone || 'local' });
 
     if (dt.isValid) {
       this.inputs[0].invalid = false;
       this.inputs[1].invalid = false;
       this.inputs[2].invalid = false;
       
-      // Convert to specified timezone or use system timezone
+      this.date = dt.toJSDate();
-      const finalDt = this.timeZone ? dt.setZone(this.timeZone) : dt;
+      this.value = dt.toUTC().toISO();
-      this.date = finalDt.toJSDate();
-      this.value = finalDt.toISO();
       this.invalid = false;
       this.dispatchEvent(new CustomEvent('value-changed', { detail: this.value, bubbles: true, composed: true }));
     } else {
@@ -455,8 +465,13 @@ class TpDateInput extends EventHelpers(ControlState(FormElement(LitElement))) {
       return;
     }
 
-    const dt = this._toDateTime(this.value);
+    let dt = this._toDateTime(this.value);
     if (dt && dt.isValid) {
+      // Convert to user's timezone for display (input values are expected to be UTC)
+      if (this.timeZone) {
+        dt = dt.setZone(this.timeZone);
+      }
+      
       // Convert luxon format parts to match display format
       this._input0 = dt.toFormat(this._getLuxonFormat(this._inputAssign[0]));
       this._input1 = dt.toFormat(this._getLuxonFormat(this._inputAssign[1]));
@@ -512,4 +527,4 @@ class TpDateInput extends EventHelpers(ControlState(FormElement(LitElement))) {
   }
 }
 
-window.customElements.define('tp-date-input', TpDateInput);
+window.customElements.define('tp-date-input', TpDateInput);