From 16249f475da198f86a8732639ec3eaa18592d1dc Mon Sep 17 00:00:00 2001
From: reduckted <reduckted@outlook.com>
Date: Sat, 7 Dec 2019 00:28:23 +1000
Subject: [PATCH] feat(accordion): use readonly arrays for inputs (#3426)

---
 src/accordion/accordion.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/accordion/accordion.ts b/src/accordion/accordion.ts
index a1528c86b4..65de46c002 100644
--- a/src/accordion/accordion.ts
+++ b/src/accordion/accordion.ts
@@ -178,7 +178,7 @@ export class NgbAccordion implements AfterContentChecked {
    * For subsequent changes use methods like `expand()`, `collapse()`, etc. and
    * the `(panelChange)` event.
    */
-  @Input() activeIds: string | string[] = [];
+  @Input() activeIds: string | readonly string[] = [];
 
   /**
    *  If `true`, only one panel could be opened at a time.