feat(dynamicSort): Add sortObjectsArray method

Closes #28

Author: Kent C. Dodds

src/index.js

@@ -4,6 +4,7 @@ import snakeToCamel from './snake-to-camel'
 import padLeft from './pad-left'
 import randomInteger from './random-integer'
 import arrayFill from './array-fill'
+import sortObjectsArray from './sort-objects-array'
 
 export {
   flatten,
@@ -12,4 +13,5 @@ export {
   padLeft,
   randomInteger,
   arrayFill,
+  sortObjectsArray,
 }

src/sort-objects-array.js

@@ -0,0 +1,27 @@
+export default sortObjectsArray
+
+/**
+ * Original Source: http://stackoverflow.com/a/4760279/3142309
+ *
+ * This method returns a function that can be passed into Array.sort to sort an array of objects by a given property.
+ * Prepending "-" to the property argument sorts the array in descending order.
+ *
+ * @param {String} property - The property to sort by
+ * @return {Function} - A function that can be passed into Array.sort
+ */
+function sortObjectsArray(property) {
+  let sortOrder = 1
+  if (property[0] === '-') {
+    sortOrder = -1
+    property = property.substr(1)
+  }
+  return function compareFunction(a, b) {
+    let result = 0
+    if (a[property] < b[property]) {
+      result = -1
+    } else if (a[property] > b[property]) {
+      result = 1
+    }
+    return result * sortOrder
+  }
+}

test/sort-objects-array.test.js

@@ -0,0 +1,43 @@
+import test from 'ava'
+import {sortObjectsArray} from '../src'
+
+test('sort an array of objects by ascending order', t => {
+    const original = [
+        {Name: "Name", Surname: "Surname"},
+        {Name:"AAA", Surname:"ZZZ"},
+        {Name: "Name", Surname: "AAA"}
+    ]
+    const expected = [
+        {Name: "Name", Surname: "AAA"},
+        {Name: "Name", Surname: "Surname"},
+        {Name:"AAA", Surname:"ZZZ"}
+    ]
+    const actual = original.slice(0).sort(sortObjectsArray('Surname'))
+    t.same(actual, expected)
+})
+
+test('sort an array of objects by descending order', t => {
+    const original = [
+        {Name: "Name", Surname: "Surname"},
+        {Name:"AAA", Surname:"ZZZ"},
+        {Name: "Name", Surname: "AAA"}
+    ]
+    const expected = [
+        {Name:"AAA", Surname:"ZZZ"},
+        {Name: "Name", Surname: "Surname"},
+        {Name: "Name", Surname: "AAA"}
+    ]
+    const actual = original.slice(0).sort(sortObjectsArray('-Surname'))
+    t.same(actual, expected)
+})
+
+test('will not sort the an array if the property doesn\'t exist', t => {
+    const original = [
+        {Name: "Name", Surname: "Surname"},
+        {Name:"AAA", Surname:"ZZZ"},
+        {Name: "Name", Surname: "AAA"}
+    ]
+    const actual = original.slice(0).sort(sortObjectsArray('Middle'))
+    t.same(actual, original)
+})
+