Add object predicate

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 {ObjectPredicate} from './lib/predicates/object';
 import {DatePredicate} from './lib/predicates/date';
 import {ErrorPredicate} from './lib/predicates/error';
 import {MapPredicate} from './lib/predicates/map';
@@ -60,6 +61,10 @@ export interface Ow {
 	 * Test the value to be an array.
 	 */
 	readonly array: ArrayPredicate;
+	/**
+	 * Test the value to be an object.
+	 */
+	readonly object: ObjectPredicate;
 	/**
 	 * Test the value to be a Date.
 	 */
@@ -196,6 +201,9 @@ Object.defineProperties(main, {
 	array: {
 		get: () => new ArrayPredicate()
 	},
+	object: {
+		get: () => new ObjectPredicate()
+	},
 	date: {
 		get: () => new DatePredicate()
 	},

source/lib/predicates/object.ts

@@ -0,0 +1,76 @@
+import is from '@sindresorhus/is';
+import * as isEqual from 'lodash.isequal';
+import {Predicate, Context} from './predicate';
+import hasItems from '../utils/has-items';
+
+export class ObjectPredicate extends Predicate<object> {
+	constructor(context?: Context) {
+		super('object', context);
+	}
+
+	/**
+	 * Test if an Object is a plain object.
+	 */
+	get plain() {
+		return this.addValidator({
+			message: () => 'Expected object to be a plain object',
+			validator: object => is.plainObject(object)
+		});
+	}
+
+	/**
+	 * Test an object to be empty.
+	 */
+	get empty() {
+		return this.addValidator({
+			message: object => `Expected object to be empty, got \`${JSON.stringify(object)}\``,
+			validator: object => Object.keys(object).length === 0
+		});
+	}
+
+	/**
+	 * Test an object to be not empty.
+	 */
+	get nonEmpty() {
+		return this.addValidator({
+			message: () => 'Expected object to not be empty',
+			validator: object => Object.keys(object).length > 0
+		});
+	}
+
+	/**
+	 * Test an object to be deeply equal to the provided object.
+	 *
+	 * @param expected Expected object to match.
+	 */
+	deepEqual(expected: {}) {
+		return this.addValidator({
+			message: object => `Expected object to be deeply equal to \`${JSON.stringify(expected)}\`, got \`${JSON.stringify(object)}\``,
+			validator: object => isEqual(object, expected)
+		});
+	}
+
+	/**
+	 * Test an object to include all the provided keys.
+	 *
+	 * @param keys The keys that should be present in the object.
+	 */
+	hasKeys(...keys: string[]) {
+		return this.addValidator({
+			message: (_, missingKeys) => `Expected object to have keys \`${JSON.stringify(missingKeys)}\``,
+			validator: object => hasItems(new Set(Object.keys(object)), keys)
+		});
+	}
+
+	/**
+	 * Test an object to include any of the provided keys.
+	 *
+	 * @param keys The keys that could be a key in the object.
+	 */
+	hasAnyKeys(...keys: string[]) {
+		return this.addValidator({
+			message: () => `Expected object to have any key of \`${JSON.stringify(keys)}\``,
+			validator: object => keys.some(key => object[key] !== undefined)
+		});
+	}
+}

source/test/object.ts

@@ -0,0 +1,42 @@
+import test from 'ava';
+import m from '..';
+
+test('object', t => {
+	t.notThrows(() => m({}, m.object));
+	t.notThrows(() => m(new Error('foo'), m.object));
+	t.throws(() => m('foo' as any, m.object), 'Expected argument to be of type `object` but received type `string`');
+	t.throws(() => m(1 as any, m.object), 'Expected argument to be of type `object` but received type `number`');
+});
+
+test('object.plain', t => {
+	t.notThrows(() => m({}, m.object.plain));
+	t.throws(() => m(new Error('foo'), m.object.plain), 'Expected object to be a plain object');
+});
+
+test('object.empty', t => {
+	t.notThrows(() => m({}, m.object.empty));
+	t.throws(() => m({unicorn: '🦄'}, m.object.empty), 'Expected object to be empty, got `{"unicorn":"🦄"}`');
+});
+
+test('object.nonEmpty', t => {
+	t.notThrows(() => m({unicorn: '🦄'}, m.object.nonEmpty));
+	t.throws(() => m({}, m.object.nonEmpty), 'Expected object to not be empty');
+});
+
+test('object.deepEqual', t => {
+	t.notThrows(() => m({unicorn: '🦄'}, m.object.deepEqual({unicorn: '🦄'})));
+	t.notThrows(() => m({unicorn: '🦄', rain: {bow: '🌈'}}, m.object.deepEqual({unicorn: '🦄', rain: {bow: '🌈'}})));
+	t.throws(() => m({unicorn: '🦄'}, m.object.deepEqual({rainbow: '🌈'})), 'Expected object to be deeply equal to `{"rainbow":"🌈"}`, got `{"unicorn":"🦄"}`');
+});
+
+test('object.hasKeys', t => {
+	t.notThrows(() => m({unicorn: '🦄'}, m.object.hasKeys('unicorn')));
+	t.notThrows(() => m({unicorn: '🦄', rainbow: '🌈'}, m.object.hasKeys('unicorn', 'rainbow')));
+	t.throws(() => m({unicorn: '🦄'}, m.object.hasKeys('unicorn', 'rainbow')), 'Expected object to have keys `["rainbow"]`');
+});
+
+test('object.hasAnyKeys', t => {
+	t.notThrows(() => m({unicorn: '🦄'}, m.object.hasAnyKeys('unicorn', 'rainbow')));
+	t.notThrows(() => m({unicorn: '🦄', rainbow: '🌈'}, m.object.hasAnyKeys('unicorn')));
+	t.throws(() => m({unicorn: '🦄'}, m.object.hasAnyKeys('foo')), 'Expected object to have any key of `["foo"]`');
+});