diff --git a/package-lock.json b/package-lock.json
index d9223688..fbb45d43 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -29,9 +29,9 @@
       }
     },
     "@types/chai": {
-      "version": "4.0.10",
-      "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.0.10.tgz",
-      "integrity": "sha512-Ejh1AXTY8lm+x91X/yar3G2z4x9RyKwdTVdyyu7Xj3dNB35fMNCnEWqTO9FgS3zjzlRNqk1MruYhgb8yhRN9rA==",
+      "version": "4.1.7",
+      "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.1.7.tgz",
+      "integrity": "sha512-2Y8uPt0/jwjhQ6EiluT0XCri1Dbplr0ZxfFXUz+ye13gaqE8u5gL5ppao1JrUYr9cIip5S6MvQzBS7Kke7U9VA==",
       "dev": true
     },
     "@types/joi": {
@@ -142,6 +142,12 @@
       "integrity": "sha1-iYUI2iIm84DfkEcoRWhJwVAaSw0=",
       "dev": true
     },
+    "assertion-error": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/assertion-error/-/assertion-error-1.1.0.tgz",
+      "integrity": "sha512-jgsaNduz+ndvGyFt3uSuWqvy4lCnIJiovtouQN5JZHOKCS2QuhEdbcQHFhVksz2N2U9hXJo8odG7ETyWlEeuDw==",
+      "dev": true
+    },
     "async": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/async/-/async-1.0.0.tgz",
@@ -335,58 +341,17 @@
       "dev": true
     },
     "chai": {
-      "version": "4.1.2",
-      "resolved": "https://registry.npmjs.org/chai/-/chai-4.1.2.tgz",
-      "integrity": "sha1-D2RYS6ZC8PKs4oBiefTwbKI61zw=",
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/chai/-/chai-4.2.0.tgz",
+      "integrity": "sha512-XQU3bhBukrOsQCuwZndwGcCVQHyZi53fQ6Ys1Fym7E4olpIqqZZhhoFJoaKVvV17lWQoXYwgWN2nF5crA8J2jw==",
       "dev": true,
       "requires": {
-        "assertion-error": "1.0.2",
-        "check-error": "1.0.2",
-        "deep-eql": "3.0.1",
-        "get-func-name": "2.0.0",
-        "pathval": "1.1.0",
-        "type-detect": "4.0.5"
-      },
-      "dependencies": {
-        "assertion-error": {
-          "version": "1.0.2",
-          "resolved": "https://registry.npmjs.org/assertion-error/-/assertion-error-1.0.2.tgz",
-          "integrity": "sha1-E8pRXYYgbaC6xm6DTdOX2HWBCUw=",
-          "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
-        },
-        "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==",
-          "dev": true,
-          "requires": {
-            "type-detect": "4.0.5"
-          }
-        },
-        "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
-        },
-        "pathval": {
-          "version": "1.1.0",
-          "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.0.tgz",
-          "integrity": "sha1-uULm1L3mUwBe9rcTYd74cn0GReA=",
-          "dev": true
-        },
-        "type-detect": {
-          "version": "4.0.5",
-          "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.0.5.tgz",
-          "integrity": "sha512-N9IvkQslUGYGC24RkJk1ba99foK6TkwC2FHAEBlQFBP0RxQZS8ZpJuAZcwiY/w9ZJHFQb1aOXBI60OdxhTrwEQ==",
-          "dev": true
-        }
+        "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": "^4.0.5"
       }
     },
     "chalk": {
@@ -433,6 +398,12 @@
         }
       }
     },
+    "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": "1.6.0",
       "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-1.6.0.tgz",
@@ -707,6 +678,15 @@
         "mimic-response": "1.0.1"
       }
     },
+    "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==",
+      "dev": true,
+      "requires": {
+        "type-detect": "^4.0.0"
+      }
+    },
     "deep-extend": {
       "version": "0.6.0",
       "resolved": "https://registry.npmjs.org/deep-extend/-/deep-extend-0.6.0.tgz",
@@ -859,6 +839,12 @@
       "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8=",
       "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-stream": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/get-stream/-/get-stream-3.0.0.tgz",
@@ -2197,6 +2183,12 @@
         "pify": "3.0.0"
       }
     },
+    "pathval": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.0.tgz",
+      "integrity": "sha1-uULm1L3mUwBe9rcTYd74cn0GReA=",
+      "dev": true
+    },
     "pify": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/pify/-/pify-3.0.0.tgz",
@@ -2718,6 +2710,12 @@
         "tslib": "1.9.0"
       }
     },
+    "type-detect": {
+      "version": "4.0.8",
+      "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.0.8.tgz",
+      "integrity": "sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==",
+      "dev": true
+    },
     "typescript": {
       "version": "2.9.2",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.9.2.tgz",
diff --git a/package.json b/package.json
index 9866f755..390b5302 100644
--- a/package.json
+++ b/package.json
@@ -32,9 +32,9 @@
   },
   "homepage": "https://github.com/balmbees/corgi#readme",
   "devDependencies": {
-    "@types/chai": "4.0.10",
+    "@types/chai": "4.1.7",
     "@types/mocha": "2.2.48",
-    "chai": "4.1.2",
+    "chai": "4.2.0",
     "check-engine": "1.7.0",
     "mocha": "3.5.3",
     "np": "3.1.0",