Array flat polyfill

Originally I was using node v11, which has that built in.

Author: romellem

package.json

@@ -14,6 +14,7 @@
   "author": "",
   "license": "MIT",
   "dependencies": {
+    "array.prototype.flat": "^1.2.1",
     "manhattan": "^1.0.0"
   }
 }

yarn.lock

@@ -2,7 +2,89 @@
 # yarn lockfile v1
 
 
+array.prototype.flat@^1.2.1:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/array.prototype.flat/-/array.prototype.flat-1.2.1.tgz#812db8f02cad24d3fab65dd67eabe3b8903494a4"
+  integrity sha512-rVqIs330nLJvfC7JqYvEWwqVr5QjYF1ib02i3YJtR/fICO6527Tjpc/e4Mvmxh3GIePPreRXMdaGyC99YphWEw==
+  dependencies:
+    define-properties "^1.1.2"
+    es-abstract "^1.10.0"
+    function-bind "^1.1.1"
+
+define-properties@^1.1.2:
+  version "1.1.3"
+  resolved "https://registry.yarnpkg.com/define-properties/-/define-properties-1.1.3.tgz#cf88da6cbee26fe6db7094f61d870cbd84cee9f1"
+  integrity sha512-3MqfYKj2lLzdMSf8ZIZE/V+Zuy+BgD6f164e8K2w7dgnpKArBDerGYpM46IYYcjnkdPNMjPk9A6VFB8+3SKlXQ==
+  dependencies:
+    object-keys "^1.0.12"
+
+es-abstract@^1.10.0:
+  version "1.12.0"
+  resolved "https://registry.yarnpkg.com/es-abstract/-/es-abstract-1.12.0.tgz#9dbbdd27c6856f0001421ca18782d786bf8a6165"
+  integrity sha512-C8Fx/0jFmV5IPoMOFPA9P9G5NtqW+4cOPit3MIuvR2t7Ag2K15EJTpxnHAYTzL+aYQJIESYeXZmDBfOBE1HcpA==
+  dependencies:
+    es-to-primitive "^1.1.1"
+    function-bind "^1.1.1"
+    has "^1.0.1"
+    is-callable "^1.1.3"
+    is-regex "^1.0.4"
+
+es-to-primitive@^1.1.1:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/es-to-primitive/-/es-to-primitive-1.2.0.tgz#edf72478033456e8dda8ef09e00ad9650707f377"
+  integrity sha512-qZryBOJjV//LaxLTV6UC//WewneB3LcXOL9NP++ozKVXsIIIpm/2c13UDiD9Jp2eThsecw9m3jPqDwTyobcdbg==
+  dependencies:
+    is-callable "^1.1.4"
+    is-date-object "^1.0.1"
+    is-symbol "^1.0.2"
+
+function-bind@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.1.tgz#a56899d3ea3c9bab874bb9773b7c5ede92f4895d"
+  integrity sha512-yIovAzMX49sF8Yl58fSCWJ5svSLuaibPxXQJFLmBObTuCr0Mf1KiPopGM9NiFjiYBCbfaa2Fh6breQ6ANVTI0A==
+
+has-symbols@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/has-symbols/-/has-symbols-1.0.0.tgz#ba1a8f1af2a0fc39650f5c850367704122063b44"
+  integrity sha1-uhqPGvKg/DllD1yFA2dwQSIGO0Q=
+
+has@^1.0.1:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/has/-/has-1.0.3.tgz#722d7cbfc1f6aa8241f16dd814e011e1f41e8796"
+  integrity sha512-f2dvO0VU6Oej7RkWJGrehjbzMAjFp5/VKPp5tTpWIV4JHHZK1/BxbFRtf/siA2SWTe09caDmVtYYzWEIbBS4zw==
+  dependencies:
+    function-bind "^1.1.1"
+
+is-callable@^1.1.3, is-callable@^1.1.4:
+  version "1.1.4"
+  resolved "https://registry.yarnpkg.com/is-callable/-/is-callable-1.1.4.tgz#1e1adf219e1eeb684d691f9d6a05ff0d30a24d75"
+  integrity sha512-r5p9sxJjYnArLjObpjA4xu5EKI3CuKHkJXMhT7kwbpUyIFD1n5PMAsoPvWnvtZiNz7LjkYDRZhd7FlI0eMijEA==
+
+is-date-object@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/is-date-object/-/is-date-object-1.0.1.tgz#9aa20eb6aeebbff77fbd33e74ca01b33581d3a16"
+  integrity sha1-mqIOtq7rv/d/vTPnTKAbM1gdOhY=
+
+is-regex@^1.0.4:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/is-regex/-/is-regex-1.0.4.tgz#5517489b547091b0930e095654ced25ee97e9491"
+  integrity sha1-VRdIm1RwkbCTDglWVM7SXul+lJE=
+  dependencies:
+    has "^1.0.1"
+
+is-symbol@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/is-symbol/-/is-symbol-1.0.2.tgz#a055f6ae57192caee329e7a860118b497a950f38"
+  integrity sha512-HS8bZ9ox60yCJLH9snBpIwv9pYUAkcuLhSA1oero1UB5y9aiQpRA8y2ex945AOtCZL1lJDeIk3G5LthswI46Lw==
+  dependencies:
+    has-symbols "^1.0.0"
+
 manhattan@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/manhattan/-/manhattan-1.0.0.tgz#f1f2fd947231a195c6611409e6ef62930c809d68"
   integrity sha512-PIHWL7/v3GAgNS+aBq3reCkBZZCC5btsyRjAUsbInkNjKpN5VRQAjTnU/+jr9AEeEi8dLy4e7Jrc3Z6iyVu3Sw==
+
+object-keys@^1.0.12:
+  version "1.0.12"
+  resolved "https://registry.yarnpkg.com/object-keys/-/object-keys-1.0.12.tgz#09c53855377575310cca62f55bb334abff7b3ed2"
+  integrity sha512-FTMyFUm2wBcGHnH2eXmz7tC6IwlqQZ6mVZ+6dm6vZ4IQIHjs6FdNsQBuKGPuUUUY6NfJw2PshC08Tn6LzLDOag==