diff --git a/dist/index.d.ts b/dist/index.d.ts
index 6e1997ca..c3eeb391 100644
--- a/dist/index.d.ts
+++ b/dist/index.d.ts
@@ -12,8 +12,8 @@ type ObjectIterable = Dictionary<any>;
 /**
  * the handlers for the iterables, specific to type
  */
-type ArrayHandler = (value?: any, index?: number, array?: ArrayIterable) => any;
-type ObjectHandler = (value?: any, key?: string, object?: ObjectIterable) => any;
+type ArrayHandler = (value: any, index: number, array: ArrayIterable) => any;
+type ObjectHandler = (value: any, key: string, object: ObjectIterable) => any;
 
 /**
  * available exports
diff --git a/index.d.ts b/index.d.ts
index 6e1997ca..c3eeb391 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -12,8 +12,8 @@ type ObjectIterable = Dictionary<any>;
 /**
  * the handlers for the iterables, specific to type
  */
-type ArrayHandler = (value?: any, index?: number, array?: ArrayIterable) => any;
-type ObjectHandler = (value?: any, key?: string, object?: ObjectIterable) => any;
+type ArrayHandler = (value: any, index: number, array: ArrayIterable) => any;
+type ObjectHandler = (value: any, key: string, object: ObjectIterable) => any;
 
 /**
  * available exports
diff --git a/package.json b/package.json
index 8db70941..a5af7c7f 100644
--- a/package.json
+++ b/package.json
@@ -33,13 +33,13 @@
     "@babel/plugin-transform-runtime": "^7.4.4",
     "@babel/preset-env": "^7.4.5",
     "@babel/preset-react": "^7.0.0",
-    "@types/jest": "^24.0.13",
-    "babel-eslint": "^10.0.1",
+    "@types/jest": "^24.0.15",
+    "babel-eslint": "^10.0.2",
     "babel-jest": "^24.8.0",
     "babel-plugin-tester": "^6.2.1",
-    "eslint": "^5.16.0",
+    "eslint": "^6.0.1",
     "eslint-config-airbnb-base": "^13.1.0",
-    "eslint-plugin-import": "^2.17.3",
+    "eslint-plugin-import": "^2.18.0",
     "fast-equals": "^2.0.0",
     "jest": "^24.8.0",
     "ts-jest": "^24.0.2"
diff --git a/yarn.lock b/yarn.lock
index f44a4a4c..e6ac1ad8 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -929,10 +929,10 @@
   resolved "https://registry.yarnpkg.com/@types/jest-diff/-/jest-diff-20.0.1.tgz#35cc15b9c4f30a18ef21852e255fdb02f6d59b89"
   integrity sha512-yALhelO3i0hqZwhjtcr6dYyaLoCHbAMshwtj6cGxTvHZAKXHsYGdff6E8EPw3xLKY0ELUTQ69Q1rQiJENnccMA==
 
-"@types/jest@^24.0.13":
-  version "24.0.14"
-  resolved "https://registry.yarnpkg.com/@types/jest/-/jest-24.0.14.tgz#bb40fec243164b2def5cfaddd0cb4d4e958c5c1c"
-  integrity sha512-IxS2AO0nOr4zrpKfRCxobQUb1bSK6ejodZ7odCzHXMjsASCI8J10N8qVQhrCjvJTc3bUjGGeuD+ytKZqyhajqQ==
+"@types/jest@^24.0.15":
+  version "24.0.15"
+  resolved "https://registry.yarnpkg.com/@types/jest/-/jest-24.0.15.tgz#6c42d5af7fe3b44ffff7cc65de7bf741e8fa427f"
+  integrity sha512-MU1HIvWUme74stAoc3mgAi+aMlgKOudgEvQDIm1v4RkrDudBh1T+NFp5sftpBAdXdx1J0PbdpJ+M2EsSOi1djA==
   dependencies:
     "@types/jest-diff" "*"
 
@@ -984,7 +984,7 @@ acorn@^6.0.1, acorn@^6.0.7:
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.1.1.tgz#7d25ae05bb8ad1f9b699108e1094ecd7884adc1f"
   integrity sha512-jPTiwtOxaHNaAPg/dmrJ/beuzLRnXtB0kQPQ8JpotKJgTB6rX6c8mlf315941pyjBSaPg8NHXS9fhP4u17DpGA==
 
-ajv@^6.5.5, ajv@^6.9.1:
+ajv@^6.10.0, ajv@^6.5.5, ajv@^6.9.1:
   version "6.10.0"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.10.0.tgz#90d0d54439da587cd7e843bfb7045f50bd22bdf1"
   integrity sha512-nffhOpkymDECQyR0mnsUtoCE8RlX38G0rYP+wgLWFyZuUyuuojSSvi/+euOiQBIn63whYwYVIIH1TvE3tu4OEg==
@@ -1134,10 +1134,10 @@ aws4@^1.8.0:
   resolved "https://registry.yarnpkg.com/aws4/-/aws4-1.8.0.tgz#f0e003d9ca9e7f59c7a508945d7b2ef9a04a542f"
   integrity sha512-ReZxvNHIOv88FlT7rxcXIIC0fPt4KZqZbOlivyWtXLt8ESx84zd3kMC6iK5jVeS2qt+g7ftS7ye4fi06X5rtRQ==
 
-babel-eslint@^10.0.1:
-  version "10.0.1"
-  resolved "https://registry.yarnpkg.com/babel-eslint/-/babel-eslint-10.0.1.tgz#919681dc099614cd7d31d45c8908695092a1faed"
-  integrity sha512-z7OT1iNV+TjOwHNLLyJk+HN+YVWX+CLE6fPD2SymJZOZQBs+QIexFjhm4keGTm8MW9xr4EC9Q0PbaLB24V5GoQ==
+babel-eslint@^10.0.2:
+  version "10.0.2"
+  resolved "https://registry.yarnpkg.com/babel-eslint/-/babel-eslint-10.0.2.tgz#182d5ac204579ff0881684b040560fdcc1558456"
+  integrity sha512-UdsurWPtgiPgpJ06ryUnuaSXC2s0WoSZnQmEpbAH65XZSdwowgN5MvyP7e88nW07FYXv72erVtpBkxyDVKhH1Q==
   dependencies:
     "@babel/code-frame" "^7.0.0"
     "@babel/parser" "^7.0.0"
@@ -1796,10 +1796,10 @@ eslint-module-utils@^2.4.0:
     debug "^2.6.8"
     pkg-dir "^2.0.0"
 
-eslint-plugin-import@^2.17.3:
-  version "2.17.3"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.17.3.tgz#00548b4434c18faebaba04b24ae6198f280de189"
-  integrity sha512-qeVf/UwXFJbeyLbxuY8RgqDyEKCkqV7YC+E5S5uOjAp4tOc8zj01JP3ucoBM8JcEqd1qRasJSg6LLlisirfy0Q==
+eslint-plugin-import@^2.18.0:
+  version "2.18.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.18.0.tgz#7a5ba8d32622fb35eb9c8db195c2090bd18a3678"
+  integrity sha512-PZpAEC4gj/6DEMMoU2Df01C5c50r7zdGIN52Yfi7CvvWaYssG7Jt5R9nFG5gmqodxNOz9vQS87xk6Izdtpdrig==
   dependencies:
     array-includes "^3.0.3"
     contains-path "^0.1.0"
@@ -1844,13 +1844,13 @@ eslint-visitor-keys@^1.0.0:
   resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#3f3180fb2e291017716acb4c9d6d5b5c34a6a81d"
   integrity sha512-qzm/XxIbxm/FHyH341ZrbnMUpe+5Bocte9xkmFMzPMjRaZMcXww+MpBptFvtU+79L362nqiLhekCxCxDPaUMBQ==
 
-eslint@^5.16.0:
-  version "5.16.0"
-  resolved "https://registry.yarnpkg.com/eslint/-/eslint-5.16.0.tgz#a1e3ac1aae4a3fbd8296fcf8f7ab7314cbb6abea"
-  integrity sha512-S3Rz11i7c8AA5JPv7xAH+dOyq/Cu/VXHiHXBPOU1k/JAM5dXqQPt3qcrhpHSorXmrpu2g0gkIBVXAqCpzfoZIg==
+eslint@^6.0.1:
+  version "6.0.1"
+  resolved "https://registry.yarnpkg.com/eslint/-/eslint-6.0.1.tgz#4a32181d72cb999d6f54151df7d337131f81cda7"
+  integrity sha512-DyQRaMmORQ+JsWShYsSg4OPTjY56u1nCjAmICrE8vLWqyLKxhFXOthwMj1SA8xwfrv0CofLNVnqbfyhwCkaO0w==
   dependencies:
     "@babel/code-frame" "^7.0.0"
-    ajv "^6.9.1"
+    ajv "^6.10.0"
     chalk "^2.1.0"
     cross-spawn "^6.0.5"
     debug "^4.0.1"
@@ -1858,18 +1858,19 @@ eslint@^5.16.0:
     eslint-scope "^4.0.3"
     eslint-utils "^1.3.1"
     eslint-visitor-keys "^1.0.0"
-    espree "^5.0.1"
+    espree "^6.0.0"
     esquery "^1.0.1"
     esutils "^2.0.2"
     file-entry-cache "^5.0.1"
     functional-red-black-tree "^1.0.1"
-    glob "^7.1.2"
+    glob-parent "^3.1.0"
     globals "^11.7.0"
     ignore "^4.0.6"
     import-fresh "^3.0.0"
     imurmurhash "^0.1.4"
     inquirer "^6.2.2"
-    js-yaml "^3.13.0"
+    is-glob "^4.0.0"
+    js-yaml "^3.13.1"
     json-stable-stringify-without-jsonify "^1.0.1"
     levn "^0.3.0"
     lodash "^4.17.11"
@@ -1877,7 +1878,6 @@ eslint@^5.16.0:
     mkdirp "^0.5.1"
     natural-compare "^1.4.0"
     optionator "^0.8.2"
-    path-is-inside "^1.0.2"
     progress "^2.0.0"
     regexpp "^2.0.1"
     semver "^5.5.1"
@@ -1886,10 +1886,10 @@ eslint@^5.16.0:
     table "^5.2.3"
     text-table "^0.2.0"
 
-espree@^5.0.1:
-  version "5.0.1"
-  resolved "https://registry.yarnpkg.com/espree/-/espree-5.0.1.tgz#5d6526fa4fc7f0788a5cf75b15f30323e2f81f7a"
-  integrity sha512-qWAZcWh4XE/RwzLJejfcofscgMc9CamR6Tn1+XRXNzrvUSSbiAjGOI/fggztjIi7y9VLPqnICMIPiGyr8JaZ0A==
+espree@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/espree/-/espree-6.0.0.tgz#716fc1f5a245ef5b9a7fdb1d7b0d3f02322e75f6"
+  integrity sha512-lJvCS6YbCn3ImT3yKkPe0+tJ+mH6ljhGNjHQH9mRtiO6gjhVAOhVXW1yjnwqGwTkK3bGbye+hb00nFNmu0l/1Q==
   dependencies:
     acorn "^6.0.7"
     acorn-jsx "^5.0.0"
@@ -3063,7 +3063,7 @@ js-levenshtein@^1.1.3:
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
   integrity sha512-RdJUflcE3cUzKiMqQgsCu06FPu9UdIJO0beYbPhHN4k6apgJtifcoCtT9bcxOpYBtpD2kCM6Sbzg4CausW/PKQ==
 
-js-yaml@^3.13.0, js-yaml@^3.13.1:
+js-yaml@^3.13.1:
   version "3.13.1"
   resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.13.1.tgz#aff151b30bfdfa8e49e05da22e7415e9dfa37847"
   integrity sha512-YfbcO7jXDdyj0DGxYVSlSeQNHbD7XPWvrVWeVUujrQEoZzWJIRrCPoyk6kL6IAjAG2IolMK4T0hNUe0HOUs5Jw==
@@ -3843,11 +3843,6 @@ path-is-absolute@^1.0.0:
   resolved "https://registry.yarnpkg.com/path-is-absolute/-/path-is-absolute-1.0.1.tgz#174b9268735534ffbc7ace6bf53a5a9e1b5c5f5f"
   integrity sha1-F0uSaHNVNP+8es5r9TpanhtcX18=
 
-path-is-inside@^1.0.2:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/path-is-inside/-/path-is-inside-1.0.2.tgz#365417dede44430d1c11af61027facf074bdfc53"
-  integrity sha1-NlQX3t5EQw0cEa9hAn+s8HS9/FM=
-
 path-key@^2.0.0, path-key@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/path-key/-/path-key-2.0.1.tgz#411cadb574c5a140d3a4b1910d40d80cc9f40b40"