Greatly simplify code

Credit to @jamestalmage for the idea

index.js

@@ -1,30 +1,38 @@
 'use strict';
-module.exports = function (ms) {
-	ms = ms || 0;
-
-	var promise = new Promise(function (resolve) {
-		setTimeout(resolve, ms);
-	});
-
-	function thunk(result) {
-		return new Promise(function (resolve) {
-			setTimeout(function () {
-				resolve(result);
-			}, ms);
-		});
-	}
+module.exports = generate(true);
+module.exports.resolve = module.exports;
+module.exports.reject = generate(false);
+
+function generate(shouldResolve) {
+	return function (ms, value) {
+		ms = ms || 0;
 
-	thunk.then = promise.then.bind(promise);
-	thunk.catch = promise.catch.bind(promise);
+		function pickAction(resolve, reject) {
+			var action = shouldResolve ? resolve : reject;
+			if (arguments.length > 1) {
+				action = action.bind(null, value);
+			}
 
-	return thunk;
-};
+			return action;
+		}
 
-module.exports.reject = function (ms, value) {
-	if (arguments.length > 1) {
-		return new Promise(function (resolve, reject) {
-			setTimeout(reject.bind(null, value), ms);
+		var promise = new Promise(function (resolve, reject) {
+			setTimeout(pickAction(resolve, reject), ms);
 		});
-	}
-	return module.exports.reject.bind(null, ms);
-};
+
+		function thunk(result) {
+			promise.catch(noop);
+			value = value || result;
+			return new Promise(function (resolve, reject) {
+				setTimeout(pickAction(resolve, reject), ms);
+			});
+		}
+
+		thunk.then = promise.then.bind(promise);
+		thunk.catch = promise.catch.bind(promise);
+
+		return thunk;
+	};
+}
+
+function noop() {}

test.js

@@ -4,14 +4,12 @@ import inRange from 'in-range';
 import fn from './';
 
 test('promise', async t => {
-	t.plan(1);
 	const end = timeSpan();
 	await fn(50);
 	t.true(inRange(end(), 30, 70), 'is delayed');
 });
 
 test('thunk', async t => {
-	t.plan(2);
 	const end = timeSpan();
 	const result = await Promise.resolve('foo').then(fn(50));
 	t.true(inRange(end(), 30, 70), 'is delayed');
@@ -24,6 +22,16 @@ test('.reject() with two arguments', async t => {
 	t.true(inRange(end(), 30, 70), 'is delayed');
 });
 
+test('.reject() with two arguments (as a thunk)', async t => {
+	const end = timeSpan();
+	await t.throws(
+		Promise.resolve('foo').then(fn.reject(50, new Error('bar'))),
+		'bar',
+		'promise is rejected with the resolution value'
+	);
+	t.true(inRange(end(), 30, 70), 'is delayed');
+});
+
 test('.reject() with one argument (thunk)', async t => {
 	const end = timeSpan();
 	await t.throws(