diff --git a/package-lock.json b/package-lock.json
index 6a15f95..1f8741f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -3239,17 +3239,17 @@
       "dev": true
     },
     "chai": {
-      "version": "4.1.2",
-      "resolved": "https://registry.npmjs.org/chai/-/chai-4.1.2.tgz",
-      "integrity": "sha1-D2RYS6ZC8PKs4oBiefTwbKI61zw=",
+      "version": "4.3.4",
+      "resolved": "https://registry.npmjs.org/chai/-/chai-4.3.4.tgz",
+      "integrity": "sha512-yS5H68VYOCtN1cjfwumDSuzn/9c+yza4f3reKXlE5rUg7SFcCEy90gJvydNgOYtblyf4Zi6jIWRnXOgErta0KA==",
       "dev": true,
       "requires": {
-        "assertion-error": "1.1.0",
-        "check-error": "1.0.2",
-        "deep-eql": "3.0.1",
-        "get-func-name": "2.0.0",
-        "pathval": "1.1.0",
-        "type-detect": "4.0.8"
+        "assertion-error": "^1.1.0",
+        "check-error": "^1.0.2",
+        "deep-eql": "^3.0.1",
+        "get-func-name": "^2.0.0",
+        "pathval": "^1.1.1",
+        "type-detect": "^4.0.5"
       }
     },
     "chalk": {
@@ -4042,7 +4042,7 @@
       "integrity": "sha512-+QeIQyN5ZuO+3Uk5DYh6/1eKO0m0YmJFGNmFHGACpf1ClL1nmlV/p4gNgbl2pJGxgXb4faqo6UE+M5ACEMyVcw==",
       "dev": true,
       "requires": {
-        "type-detect": "4.0.8"
+        "type-detect": "^4.0.0"
       }
     },
     "deep-extend": {
@@ -9355,9 +9355,9 @@
       }
     },
     "pathval": {
-      "version": "1.1.0",
-      "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.0.tgz",
-      "integrity": "sha1-uULm1L3mUwBe9rcTYd74cn0GReA=",
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.1.tgz",
+      "integrity": "sha512-Dp6zGqpTdETdR63lehJYPeIOqpiNBNtc7BpWSLrOje7UaIsE5aY92r/AunQA7rsXvet3lrJ3JnZX29UPTKXyKQ==",
       "dev": true
     },
     "pbkdf2": {
diff --git a/package.json b/package.json
index da03c12..069a6d3 100644
--- a/package.json
+++ b/package.json
@@ -52,7 +52,7 @@
   "devDependencies": {
     "@polymer/iron-test-helpers": "3.0.1",
     "babel-eslint": "9.0.0",
-    "chai": "4.1.2",
+    "chai": "4.3.4",
     "eslint": "5.6.0",
     "eslint-config-semistandard": "12.0.1",
     "eslint-config-standard": "12.0.0",