Simplify object check and eliminate lodash depdency (#936)

* Simplify object check and eliminate lodash depdency, mirroring reduxjs/redux#2599 .

* Add missing files.

* Replace isPlainObject with unmodified version from Redux

* Also replace the spec with the unmodified version

Author: sven971105

.babelrc

@@ -34,14 +34,8 @@
         ["transform-es2015-modules-commonjs", { "loose": true }]
       ]
     },
-    "es": {
-      "plugins": [
-        "./build/use-lodash-es"
-      ]
-    },
     "rollup": {
       "plugins": [
-        "./build/use-lodash-es",
         "external-helpers"
       ]
     }

build/use-lodash-es.js

@@ -45,15 +45,13 @@
   "dependencies": {
     "hoist-non-react-statics": "^2.5.0",
     "invariant": "^2.2.4",
-    "lodash": "^4.17.5",
-    "lodash-es": "^4.17.5",
     "loose-envify": "^1.1.0",
     "prop-types": "^15.6.1"
   },
   "devDependencies": {
     "babel-cli": "^6.26.0",
     "babel-core": "^6.26.0",
-    "babel-eslint": "^8.2.2",
+    "babel-eslint": "^8.2.3",
     "babel-plugin-check-es2015-constants": "^6.3.13",
     "babel-plugin-external-helpers": "^6.22.0",
     "babel-plugin-syntax-jsx": "^6.3.13",
@@ -83,17 +81,17 @@
     "cross-env": "^5.1.4",
     "es3ify": "^0.2.0",
     "eslint": "^4.19.1",
-    "eslint-plugin-import": "^2.10.0",
+    "eslint-plugin-import": "^2.11.0",
     "eslint-plugin-react": "^7.7.0",
     "glob": "^7.1.1",
     "jest": "^22.4.3",
-    "react": "^16.3.0",
-    "react-dom": "^16.3.0",
-    "react-test-renderer": "^16.3.0",
+    "react": "^16.3.2",
+    "react-dom": "^16.3.2",
+    "react-test-renderer": "^16.3.2",
     "redux": "^3.0.0",
     "rimraf": "^2.6.2",
     "rollup": "^0.57.1",
-    "rollup-plugin-babel": "^3.0.3",
+    "rollup-plugin-babel": "^3.0.4",
     "rollup-plugin-commonjs": "^9.1.0",
     "rollup-plugin-node-resolve": "^3.3.0",
     "rollup-plugin-replace": "^2.0.0",

package-lock.json

@@ -0,0 +1,14 @@
+/**
+ * @param {any} obj The object to inspect.
+ * @returns {boolean} True if the argument appears to be a plain object.
+ */
+export default function isPlainObject(obj) {
+  if (typeof obj !== 'object' || obj === null) return false
+
+  let proto = obj
+  while (Object.getPrototypeOf(proto) !== null) {
+    proto = Object.getPrototypeOf(proto)
+  }
+
+  return Object.getPrototypeOf(obj) === proto
+}

package.json

@@ -1,4 +1,4 @@
-import isPlainObject from 'lodash/isPlainObject'
+import isPlainObject from './isPlainObject'
 import warning from './warning'
 
 export default function verifyPlainObject(value, displayName, methodName) {

src/utils/isPlainObject.js

@@ -0,0 +1,21 @@
+import isPlainObject from '../../src/utils/isPlainObject'
+import vm from 'vm'
+
+describe('isPlainObject', () => {
+  it('returns true only if plain object', () => {
+    function Test() {
+      this.prop = 1
+    }
+
+    const sandbox = { fromAnotherRealm: false }
+    vm.runInNewContext('fromAnotherRealm = {}', sandbox)
+
+    expect(isPlainObject(sandbox.fromAnotherRealm)).toBe(true)
+    expect(isPlainObject(new Test())).toBe(false)
+    expect(isPlainObject(new Date())).toBe(false)
+    expect(isPlainObject([1, 2, 3])).toBe(false)
+    expect(isPlainObject(null)).toBe(false)
+    expect(isPlainObject()).toBe(false)
+    expect(isPlainObject({ x: 1, y: 2 })).toBe(true)
+  })
+})