From f2be585bf2ac549728759d1b3c7c9d801ad283ab Mon Sep 17 00:00:00 2001
From: Sam Verschueren <sam.verschueren@gmail.com>
Date: Sat, 25 Nov 2017 11:25:55 +0100
Subject: [PATCH] Add date predicate (#26)

---
 source/index.ts               |  8 ++++++++
 source/lib/predicates/date.ts | 31 +++++++++++++++++++++++++++++++
 source/test/date.ts           | 19 +++++++++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 source/lib/predicates/date.ts
 create mode 100644 source/test/date.ts

diff --git a/source/index.ts b/source/index.ts
index c2ab83c..748f6db 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -4,6 +4,7 @@ import {StringPredicate} from './lib/predicates/string';
 import {NumberPredicate} from './lib/predicates/number';
 import {BooleanPredicate} from './lib/predicates/boolean';
 import {ArrayPredicate} from './lib/predicates/array';
+import {DatePredicate} from './lib/predicates/date';
 
 export interface Ow {
 	(value: any, predicate: Predicate): void;
@@ -23,6 +24,10 @@ export interface Ow {
 	 * Test the value to be an array.
 	 */
 	array: ArrayPredicate;
+	/**
+	 * Test the value to be a Date.
+	 */
+	date: DatePredicate;
 }
 
 const main = (value: any, predicate: Predicate) => {
@@ -46,6 +51,9 @@ Object.defineProperties(main, {
 	},
 	array: {
 		get: () => new ArrayPredicate()
+	},
+	date: {
+		get: () => new DatePredicate()
 	}
 });
 
diff --git a/source/lib/predicates/date.ts b/source/lib/predicates/date.ts
new file mode 100644
index 0000000..0c3858e
--- /dev/null
+++ b/source/lib/predicates/date.ts
@@ -0,0 +1,31 @@
+import {Predicate, Context} from './predicate';
+
+export class DatePredicate extends Predicate<Date> {
+	constructor(context?: Context) {
+		super('date', context);
+	}
+
+	/**
+	 * Test a date to be before another date.
+	 *
+	 * @param date Maximum value.
+	 */
+	before(date: Date) {
+		return this.addValidator({
+			message: value => `Expected ${value.toISOString()} to be before ${date.toISOString()}`,
+			validator: value => value.getTime() < date.getTime()
+		});
+	}
+
+	/**
+	 * Test a date to be before another date.
+	 *
+	 * @param date Minimum value.
+	 */
+	after(date: Date) {
+		return this.addValidator({
+			message: value => `Expected ${value.toISOString()} to be after ${date.toISOString()}`,
+			validator: value => value.getTime() > date.getTime()
+		});
+	}
+}
diff --git a/source/test/date.ts b/source/test/date.ts
new file mode 100644
index 0000000..0e10cb4
--- /dev/null
+++ b/source/test/date.ts
@@ -0,0 +1,19 @@
+import test from 'ava';
+import m from '..';
+
+test('date', t => {
+	t.notThrows(() => m(new Date(), m.date));
+	t.throws(() => m('12', m.date), 'Expected argument to be of type `date` but received type `string`');
+});
+
+test('date.before', t => {
+	t.notThrows(() => m(new Date('2017-11-25'), m.date.before(new Date('2017-11-26'))));
+	t.notThrows(() => m(new Date('2017-11-25T12:00:00Z'), m.date.before(new Date('2017-11-25T12:00:01Z'))));
+	t.throws(() => m(new Date('2017-11-25T12:00:00Z'), m.date.before(new Date('2017-11-25T12:00:00Z'))), 'Expected 2017-11-25T12:00:00.000Z to be before 2017-11-25T12:00:00.000Z');
+});
+
+test('date.after', t => {
+	t.notThrows(() => m(new Date('2017-11-26'), m.date.after(new Date('2017-11-25'))));
+	t.notThrows(() => m(new Date('2017-11-26T12:00:00Z'), m.date.after(new Date('2017-11-26T11:59:59Z'))));
+	t.throws(() => m(new Date('2017-11-26T12:00:00Z'), m.date.after(new Date('2017-11-26T12:00:00Z'))), 'Expected 2017-11-26T12:00:00.000Z to be after 2017-11-26T12:00:00.000Z');
+});