ran npm run tdd & generated TDD

test/groupBy/groupBy.js

@@ -0,0 +1,5 @@
+module.exports = (arr, func) =>
+arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => {
+acc[val] = (acc[val] || []).concat(arr[i]);
+return acc;
+}, {});

test/groupBy/groupBy.test.js

@@ -0,0 +1,13 @@
+const test = require('tape');
+const groupBy = require('./groupBy.js');
+
+test('Testing groupBy', (t) => {
+	//For more information on all the methods supported by tape
+	//Please go to https://github.com/substack/tape
+	t.true(typeof groupBy === 'function', 'groupBy is a Function');
+	//t.deepEqual(groupBy(args..), 'Expected');
+	//t.equal(groupBy(args..), 'Expected');
+	//t.false(groupBy(args..), 'Expected');
+	//t.throws(groupBy(args..), 'Expected');
+	t.end();
+});