Apply fix for #226

Author: danielkcz

package.json

@@ -38,31 +38,31 @@
     "react": "^16.8.0"
   },
   "devDependencies": {
-    "@size-limit/preset-small-lib": "2.1.4",
-    "@size-limit/time": "2.1.4",
-    "@testing-library/jest-dom": "4.1.0",
-    "@testing-library/react": "9.1.4",
+    "@size-limit/preset-small-lib": "2.1.6",
+    "@size-limit/time": "2.1.6",
+    "@testing-library/react": "9.3.0",
     "@testing-library/react-hooks": "1.1.0",
+    "@testing-library/jest-dom": "4.1.2",
     "@types/jest": "24.0.18",
-    "@types/node": "12.7.4",
-    "@types/react": "16.9.2",
-    "@types/react-dom": "16.9.0",
-    "coveralls": "3.0.6",
-    "husky": "3.0.5",
+    "@types/node": "12.7.12",
+    "@types/react": "16.9.5",
+    "@types/react-dom": "16.9.1",
+    "coveralls": "3.0.7",
+    "husky": "3.0.9",
     "jest": "24.9.0",
     "jest-environment-jsdom": "24.9.0",
     "jest-mock-console": "1.0.0",
-    "lint-staged": "9.2.5",
-    "mobx": "5.13.0",
+    "lint-staged": "9.4.2",
+    "mobx": "5.14.0",
     "prettier": "1.18.2",
     "react": "16.9.0",
     "react-dom": "16.9.0",
     "react-test-renderer": "16.9.0",
     "rimraf": "3.0.0",
-    "size-limit": "2.1.4",
-    "ts-jest": "24.0.2",
+    "size-limit": "2.1.6",
+    "ts-jest": "24.1.0",
     "tsdx": "^0.9.1",
-    "tslint": "5.19.0",
+    "tslint": "5.20.0",
     "tslint-config-prettier": "1.18.0",
     "typescript": "3.4.5"
   },

src/useObserver.ts

@@ -97,7 +97,10 @@ export function useObserver<T>(
             forceUpdate()
         }
 
-        return () => reactionTrackingRef.current!.reaction.dispose()
+        return () => {
+            reactionTrackingRef.current!.reaction.dispose()
+            reactionTrackingRef.current = null
+        }
     }, [])
 
     // render the original component, but have the