diff --git a/package-lock.json b/package-lock.json
index 019ec1d..d3809df 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4300,17 +4300,26 @@
       "dev": true
     },
     "chai": {
-      "version": "4.1.2",
-      "resolved": "https://registry.npmjs.org/chai/-/chai-4.1.2.tgz",
-      "integrity": "sha1-D2RYS6ZC8PKs4oBiefTwbKI61zw=",
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/chai/-/chai-4.5.0.tgz",
+      "integrity": "sha512-RITGBfijLkBddZvnn8jdqoTypxvqbOLYQkGGxXzeFjVHvudaPw0HNFD9x928/eUwYWd2dPCugVqspGALTZZQKw==",
       "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": "^1.0.3",
+        "deep-eql": "^4.1.3",
+        "get-func-name": "^2.0.2",
+        "loupe": "^2.3.6",
+        "pathval": "^1.1.1",
+        "type-detect": "^4.1.0"
+      },
+      "dependencies": {
+        "type-detect": {
+          "version": "4.1.0",
+          "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.1.0.tgz",
+          "integrity": "sha512-Acylog8/luQ8L7il+geoSxhEkazvkslg7PSNKOX59mbB9cOveP5aq9h74Y7YU8yDpJwetzQQrfIwtf4Wp4LKcw==",
+          "dev": true
+        }
       }
     },
     "chalk": {
@@ -4337,10 +4346,13 @@
       "dev": true
     },
     "check-error": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/check-error/-/check-error-1.0.2.tgz",
-      "integrity": "sha1-V00xLt2Iu13YkS6Sht1sCu1KrII=",
-      "dev": true
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/check-error/-/check-error-1.0.3.tgz",
+      "integrity": "sha512-iKEoDYaRmd1mxM90a2OEfWhjsjPpYPuQ+lMYsoxB126+t8fw7ySEO48nmDg5COTjxDI65/Y2OWpeEHk3ZOe8zg==",
+      "dev": true,
+      "requires": {
+        "get-func-name": "^2.0.2"
+      }
     },
     "check-types": {
       "version": "7.4.0",
@@ -5090,12 +5102,12 @@
       "dev": true
     },
     "deep-eql": {
-      "version": "3.0.1",
-      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-3.0.1.tgz",
-      "integrity": "sha512-+QeIQyN5ZuO+3Uk5DYh6/1eKO0m0YmJFGNmFHGACpf1ClL1nmlV/p4gNgbl2pJGxgXb4faqo6UE+M5ACEMyVcw==",
+      "version": "4.1.4",
+      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-4.1.4.tgz",
+      "integrity": "sha512-SUwdGfqdKOwxCPeVYjwSyRpJ7Z+fhpwIAtmCUdZIWZ/YP5R9WAsyuSgpLVDi9bjWoN2LXHNss/dk3urXtdQxGg==",
       "dev": true,
       "requires": {
-        "type-detect": "4.0.8"
+        "type-detect": "^4.0.0"
       }
     },
     "deep-extend": {
@@ -7509,9 +7521,9 @@
       "dev": true
     },
     "get-func-name": {
-      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/get-func-name/-/get-func-name-2.0.0.tgz",
-      "integrity": "sha1-6td0q+5y4gQJQzoGY2YCPdaIekE=",
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/get-func-name/-/get-func-name-2.0.2.tgz",
+      "integrity": "sha512-8vXOvuE167CtIc3OyItco7N/dpRtBbYOsPsXCz7X/PMnlGjYjSGuZJgM1Y7mmew7BKf9BqvLX2tnOVy1BBUsxQ==",
       "dev": true
     },
     "get-stdin": {
@@ -9345,6 +9357,15 @@
         "signal-exit": "^3.0.0"
       }
     },
+    "loupe": {
+      "version": "2.3.7",
+      "resolved": "https://registry.npmjs.org/loupe/-/loupe-2.3.7.tgz",
+      "integrity": "sha512-zSMINGVYkdpYSOBmLi0D1Uo7JU9nVdQKrHxC8eYlV+9YKK9WePqAlL7lSlorG/U2Fw1w0hTBmaa/jrQ3UbPHtA==",
+      "dev": true,
+      "requires": {
+        "get-func-name": "^2.0.1"
+      }
+    },
     "lower-case": {
       "version": "1.1.4",
       "resolved": "https://registry.npmjs.org/lower-case/-/lower-case-1.1.4.tgz",
@@ -10462,9 +10483,9 @@
       }
     },
     "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 c1e43c7..1baaeac 100644
--- a/package.json
+++ b/package.json
@@ -61,7 +61,7 @@
   "devDependencies": {
     "@polymer/iron-test-helpers": "3.0.1",
     "babel-eslint": "9.0.0",
-    "chai": "4.1.2",
+    "chai": "4.5.0",
     "eslint": "5.6.0",
     "eslint-config-semistandard": "12.0.1",
     "eslint-config-standard": "12.0.0",