working flat() polyfill for jest

packages/builder/package.json

@@ -49,6 +49,9 @@
     ],
     "setupFilesAfterEnv": [
       "@testing-library/jest-dom/extend-expect"
+    ],
+    "setupFiles": [
+      "./scripts/jestSetup.js"
     ]
   },
   "eslintConfig": {

packages/builder/scripts/jestSetup.js

@@ -0,0 +1,25 @@
+if (!Array.prototype.flat) {
+  Object.defineProperty(Array.prototype, "flat", {
+    configurable: true,
+    value: function flat() {
+      var depth = isNaN(arguments[0]) ? 1 : Number(arguments[0])
+
+      return depth
+        ? Array.prototype.reduce.call(
+            this,
+            function(acc, cur) {
+              if (Array.isArray(cur)) {
+                acc.push.apply(acc, flat.call(cur, depth - 1))
+              } else {
+                acc.push(cur)
+              }
+
+              return acc
+            },
+            []
+          )
+        : Array.prototype.slice.call(this)
+    },
+    writable: true,
+  })
+}

packages/builder/tests/fetchBindableProperties.spec.js

@@ -1,10 +1,4 @@
 import fetchBindableProperties from "../src/builderStore/fetchBindableProperties"
-import { flat } from "lodash"
-
-// supports running jest on Node 10.x
-if (!Array.flat) {
-  Array.flat = flat
-}
 
 describe("fetch bindable properties", () => {