diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+
+
+
+
+
+
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
new file mode 100644
index 0000000..1fa8fb1
--- /dev/null
+++ b/.idea/workspace.xml
@@ -0,0 +1,73 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 1645820743983
+
+
+ 1645820743983
+
+
+
+
+
+
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/package.json b/package.json
index d07c4b4..a1f4653 100644
--- a/package.json
+++ b/package.json
@@ -53,6 +53,7 @@
"@types/zen-observable": "^0.8.0",
"@typescript-eslint/eslint-plugin": "^2.20.0",
"@typescript-eslint/parser": "^2.20.0",
+ "@ungap/weakrefs": "^0.2.0",
"ava": "^3.3.0",
"del-cli": "^2.0.0",
"eslint-config-xo-typescript": "^0.26.0",
diff --git a/test/test.ts b/test/test.ts
index 113be26..f9b6091 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -7,6 +7,7 @@ import {JSDOM} from 'jsdom';
import {Subject, Observable} from 'rxjs';
import tempy = require('tempy');
import ZenObservable = require('zen-observable');
+import {WeakRef} from '@ungap/weakrefs'
import is, {assert, AssertionTypeDescription, Primitive, TypedArray, TypeName} from '../source';
class PromiseSubclassFixture extends Promise {}
@@ -339,7 +340,7 @@ const types = new Map([
is: is.weakRef,
assert: assert.weakRef,
fixtures: [
- new window.WeakRef({})
+ window.WeakRef ? new window.WeakRef({}) : new WeakRef({})
],
typename: 'WeakRef'
}],