Add WeakSet predicate (#44)

source/index.ts

@@ -8,6 +8,7 @@ import {DatePredicate} from './lib/predicates/date';
 import {ErrorPredicate} from './lib/predicates/error';
 import {MapPredicate} from './lib/predicates/map';
 import {SetPredicate} from './lib/predicates/set';
+import {WeakSetPredicate} from './lib/predicates/weak-set';
 
 /**
  * @hidden
@@ -74,6 +75,10 @@ export interface Ow {
 	 * Test the value to be a Set.
 	 */
 	readonly set: SetPredicate;
+	/**
+	 * Test the value to be a WeakSet.
+	 */
+	readonly weakSet: WeakSetPredicate;
 	/**
 	 * Test the value to be a Function.
 	 */
@@ -196,6 +201,9 @@ Object.defineProperties(main, {
 	set: {
 		get: () => new SetPredicate()
 	},
+	weakSet: {
+		get: () => new WeakSetPredicate()
+	},
 	function: {
 		get: () => new Predicate('function')
 	},

source/lib/predicates/weak-set.ts

@@ -0,0 +1,47 @@
+import {Predicate, Context} from './predicate';
+
+export class WeakSetPredicate extends Predicate<WeakSet<any>> {
+	constructor(context?: Context) {
+		super('weakSet', context);
+	}
+
+	/**
+	 * Test a WeakSet to include all the provided items. The items are tested by identity, not structure.
+	 *
+	 * @param items The items that should be a item in the WeakSet.
+	 */
+	has(...items: any[]) {
+		const missingItems: any[] = [];
+
+		return this.addValidator({
+			message: () => `Expected WeakSet to have items \`${JSON.stringify(missingItems)}\``,
+			validator: set => {
+				for (const key of items) {
+					if (set.has(key)) {
+						continue;
+					}
+
+					missingItems.push(key);
+
+					if (missingItems.length === 5) {
+						return false;
+					}
+				}
+
+				return missingItems.length === 0;
+			}
+		});
+	}
+
+	/**
+	 * Test a WeakSet to include any of the provided items. The items are tested by identity, not structure.
+	 *
+	 * @param items The items that could be a item in the WeakSet.
+	 */
+	hasAny(...items: any[]) {
+		return this.addValidator({
+			message: () => `Expected WeakSet to have any item of \`${JSON.stringify(items)}\``,
+			validator: set => items.some(item => set.has(item))
+		});
+	}
+}

source/test/weak-set.ts

@@ -0,0 +1,29 @@
+import test from 'ava';
+import m from '..';
+
+const unicorn: any = {unicorn: '🦄'};
+const rainbow: any = {rainbow: '🌈'};
+const rocket: any = {rocket: '🚀'};
+
+test('weakSet', t => {
+	t.notThrows(() => m(new WeakSet(), m.weakSet));
+	t.notThrows(() => m(new WeakSet([{unicorn: '🦄'}]), m.weakSet));
+	t.notThrows(() => m(new WeakSet([unicorn]), m.weakSet));
+	t.throws(() => m(12 as any, m.weakSet), 'Expected argument to be of type `weakSet` but received type `number`');
+});
+
+test('weakSet.has', t => {
+	const keys = [{x: 1}, {x: 2}, {x: 3}, {x: 4}, {x: 5}, {x: 6}, {x: 7}, {x: 8}, {x: 9}, {x: 10}];
+
+	t.notThrows(() => m(new WeakSet([unicorn]), m.weakSet.has(unicorn)));
+	t.notThrows(() => m(new WeakSet([unicorn, rainbow]), m.weakSet.has(unicorn, rainbow)));
+	t.throws(() => m(new WeakSet([unicorn, rainbow]), m.weakSet.has(rocket)), 'Expected WeakSet to have items `[{"rocket":"🚀"}]`');
+	t.throws(() => m(new WeakSet([unicorn, rocket]), m.weakSet.has(rainbow, rocket)), 'Expected WeakSet to have items `[{"rainbow":"🌈"}]`');
+	t.throws(() => m(new WeakSet([keys[1], keys[3]]), m.weakSet.has(...keys)), 'Expected WeakSet to have items `[{"x":1},{"x":3},{"x":5},{"x":6},{"x":7}]`');
+});
+
+test('weakSet.hasAny', t => {
+	t.notThrows(() => m(new WeakSet([unicorn]), m.weakSet.hasAny(unicorn, rainbow)));
+	t.notThrows(() => m(new WeakSet([unicorn, rainbow]), m.weakSet.hasAny(unicorn)));
+	t.throws(() => m(new WeakSet([unicorn, rainbow]), m.weakSet.hasAny(rocket)), 'Expected WeakSet to have any item of `[{"rocket":"🚀"}]`');
+});