Add replacement utils for lodash modules + tests

Author: frankychung

src/utils/identity.js

@@ -0,0 +1,3 @@
+export default function identity(value) {
+  return value;
+}

src/utils/isPlainObject.js

@@ -0,0 +1,3 @@
+export default function isPlainObject(obj) {
+  return typeof obj == 'object' && Object.getPrototypeOf(obj) === Object.prototype;
+}

src/utils/pick.js

@@ -0,0 +1,8 @@
+export default function pick(obj, fn) {
+  return Object.keys(obj).reduce((result, key) => {
+    if (fn(obj[key])) {
+      result[key] = obj[key];
+    }
+    return result;
+  }, {});
+}

test/utils/identity.spec.js

@@ -0,0 +1,11 @@
+import expect from 'expect';
+import identity from '../../src/utils/identity';
+
+describe('Utils', () => {
+  describe('identity', () => {
+    it('should return first argument passed to it', () => {
+      var test = { 'a': 1 };
+      expect(identity(test, 'test')).toEqual(test);
+    });
+  });
+});

test/utils/isPlainObject.spec.js

@@ -0,0 +1,17 @@
+import expect from 'expect';
+import isPlainObject from '../../src/utils/isPlainObject';
+
+describe('Utils', () => {
+  describe('isPlainObject', () => {
+    it('should return true only if plain object', () => {
+      function Test() {
+        this.prop = 1;
+      }
+
+      expect(isPlainObject(new Test())).toBe(false);
+      expect(isPlainObject(new Date())).toBe(false);
+      expect(isPlainObject([1, 2, 3])).toBe(false);
+      expect(isPlainObject({ 'x': 1, 'y': 2 })).toBe(true);
+    });
+  });
+});

test/utils/pick.spec.js

@@ -0,0 +1,11 @@
+import expect from 'expect';
+import pick from '../../src/utils/pick';
+
+describe('Utils', () => {
+  describe('pick', () => {
+    it('should return object with picked values', () => {
+      const test = { 'name': 'lily', 'age': 20 };
+      expect(pick(test, x => typeof x === 'string')).toEqual({ 'name': 'lily' });
+    });
+  });
+});