From 7b899294b68a27900effa0dd86d1d941323107c0 Mon Sep 17 00:00:00 2001
From: Thomas Lebeau <thomas.lebeau@datadoghq.com>
Date: Wed, 15 May 2024 15:51:29 +0200
Subject: [PATCH] implement WeakRef types

---
 packages/core/src/browser/types.ts                   | 12 ++++++++++++
 .../view/viewMetrics/trackCumulativeLayoutShift.ts   |  3 +++
 tsconfig.base.json                                   |  2 +-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/browser/types.ts b/packages/core/src/browser/types.ts
index 54f09932b7..2dc0970a26 100644
--- a/packages/core/src/browser/types.ts
+++ b/packages/core/src/browser/types.ts
@@ -39,6 +39,18 @@ export interface VisualViewport extends EventTarget {
   ): void
 }
 
+export interface WeakRef<T extends object> {
+  readonly [Symbol.toStringTag]: 'WeakRef'
+
+  deref(): T | undefined
+}
+
+export interface WeakRefConstructor {
+  readonly prototype: WeakRef<any>
+
+  new <T extends object>(target: T): WeakRef<T>
+}
+
 // Those are native API types that are not official supported by TypeScript yet
 
 export interface CookieStore extends EventTarget {}
diff --git a/packages/rum-core/src/domain/view/viewMetrics/trackCumulativeLayoutShift.ts b/packages/rum-core/src/domain/view/viewMetrics/trackCumulativeLayoutShift.ts
index a19a165342..9c9de27dce 100644
--- a/packages/rum-core/src/domain/view/viewMetrics/trackCumulativeLayoutShift.ts
+++ b/packages/rum-core/src/domain/view/viewMetrics/trackCumulativeLayoutShift.ts
@@ -1,5 +1,6 @@
 import { round, find, ONE_SECOND, noop } from '@datadog/browser-core'
 import type { RelativeTime } from '@datadog/browser-core'
+import type { WeakRef, WeakRefConstructor } from 'packages/core/src/browser/types'
 import { isElementNode } from '../../../browser/htmlDomUtils'
 import type { LifeCycle } from '../../lifeCycle'
 import { LifeCycleEventType } from '../../lifeCycle'
@@ -13,6 +14,8 @@ export interface CumulativeLayoutShift {
   targetSelector?: string
 }
 
+declare const WeakRef: WeakRefConstructor
+
 /**
  * Track the cumulative layout shifts (CLS).
  * Layout shifts are grouped into session windows.
diff --git a/tsconfig.base.json b/tsconfig.base.json
index 747cb83e7d..409a6763f4 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -11,7 +11,7 @@
     "sourceMap": true,
 
     "types": [],
-    "lib": ["ES2022", "DOM"],
+    "lib": ["ES2016", "DOM"],
 
     "paths": {
       "@datadog/browser-core": ["./packages/core/src"],