ref: IE10 is not supported in Mocha v5

Author: kamilogorek

package.json

@@ -35,7 +35,7 @@
     "jest": "^22.4.3",
     "karma-sinon": "^1.0.5",
     "lerna": "3.4.0",
-    "mocha": "^5.1.1",
+    "mocha": "^4.1.0",
     "npm-run-all": "^4.1.2",
     "prettier": "^1.14.0",
     "prettier-check": "^2.0.0",