fix: ensure Symbol.for exists before calling it (#366)

For IE11 compatibility Closes #365
immerjs · May 14, 2019 · c8ecbad · c8ecbad
1 parent 4443cac
commit c8ecbad
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/src/common.js b/src/common.js
@@ -4,12 +4,14 @@ export const NOTHING =
         : {["immer-nothing"]: true}
 
 export const DRAFTABLE =
-    typeof Symbol !== "undefined"
+    typeof Symbol !== "undefined" && Symbol.for
         ? Symbol.for("immer-draftable")
         : "__$immer_draftable"
 
 export const DRAFT_STATE =
-    typeof Symbol !== "undefined" ? Symbol.for("immer-state") : "__$immer_state"
+    typeof Symbol !== "undefined" && Symbol.for
+        ? Symbol.for("immer-state")
+        : "__$immer_state"
 
 export function isDraft(value) {
     return !!value && !!value[DRAFT_STATE]