diff --git a/package-lock.json b/package-lock.json
index 40f676a..a461d90 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -479,9 +479,9 @@
       "dev": true
     },
     "chai": {
-      "version": "3.5.0",
-      "resolved": "https://registry.npmjs.org/chai/-/chai-3.5.0.tgz",
-      "integrity": "sha1-TQJjewZ/6Vi9v906QOxW/vc3Mkc=",
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/chai/-/chai-4.0.1.tgz",
+      "integrity": "sha1-nkHoCOF6fxCAdyHirFpYnVuwkII=",
       "dev": true
     },
     "chalk": {
@@ -490,6 +490,12 @@
       "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
       "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
+    },
     "ci-info": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-1.0.0.tgz",
@@ -787,15 +793,15 @@
       "dev": true
     },
     "deep-eql": {
-      "version": "0.1.3",
-      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-0.1.3.tgz",
-      "integrity": "sha1-71WKyrjeJSBs1xOQbXTlaTDrafI=",
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-2.0.2.tgz",
+      "integrity": "sha1-sbrAblbwp2d3aG1Qyf63XC7XZ5o=",
       "dev": true,
       "dependencies": {
         "type-detect": {
-          "version": "0.1.1",
-          "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-0.1.1.tgz",
-          "integrity": "sha1-C6XsKohWQORw6k6FBZcZANrFiCI=",
+          "version": "3.0.0",
+          "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-3.0.0.tgz",
+          "integrity": "sha1-RtDMhVOrt7E6NSsNbeov1Y8tm1U=",
           "dev": true
         }
       }
@@ -1234,6 +1240,12 @@
       "integrity": "sha1-9wLmMSfn4jHBYKgMFVSstw1QR+U=",
       "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=",
+      "dev": true
+    },
     "get-stdin": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/get-stdin/-/get-stdin-4.0.1.tgz",
@@ -2380,6 +2392,12 @@
       "integrity": "sha1-WcRPfuSR2nBNpBXaWkBwuk+P5EE=",
       "dev": true
     },
+    "pathval": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.0.tgz",
+      "integrity": "sha1-uULm1L3mUwBe9rcTYd74cn0GReA=",
+      "dev": true
+    },
     "pbkdf2": {
       "version": "3.0.12",
       "resolved": "https://registry.npmjs.org/pbkdf2/-/pbkdf2-3.0.12.tgz",
@@ -3046,9 +3064,9 @@
       "dev": true
     },
     "type-detect": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-1.0.0.tgz",
-      "integrity": "sha1-diIXzAbbJY7EiQihKY6LlRIejqI=",
+      "version": "4.0.3",
+      "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.0.3.tgz",
+      "integrity": "sha1-Dj8mcLRAmbC0bChNE2p+9Jx0wuo=",
       "dev": true
     },
     "typedarray": {
diff --git a/package.json b/package.json
index d24d9ef..a1bc99a 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,7 @@
   },
   "devDependencies": {
     "browserify": "^14.3.0",
-    "chai": "^3.5.0",
+    "chai": "^4.0.1",
     "codacy-coverage": "^2.0.2",
     "coveralls": "^2.13.1",
     "eslint": "^3.19.0",