Add array.exactShape predicate

source/predicates/array.ts

@@ -2,6 +2,8 @@ import isEqual = require('lodash.isequal');
 import {BasePredicate} from './base-predicate';
 import {Predicate, PredicateOptions} from './predicate';
 import ow from '..';
+import {Shape} from './object';
+import {exact} from '../utils/match-shape';
 
 export class ArrayPredicate<T = unknown> extends Predicate<T[]> {
 	/**
@@ -158,4 +160,25 @@ export class ArrayPredicate<T = unknown> extends Predicate<T[]> {
 			}
 		});
 	}
+
+	/**
+	Test all elements in the array to match the exact shape with the provided predicate.
+
+	The predicates is an array which describes how the tested array should look like. Each predicate placed at the nth index should be applied also to the item at the same index.
+
+	@param predicates - The predicate placed at the nth index should be applied also to the item at the same index.
+
+	@example
+	```
+	ow(['1', 2], ow.array.exactShape([ow.string, ow.number]));
+	```
+	*/
+	exactShape(predicates: Predicate[]) {
+		const shape = predicates as unknown as Shape;
+
+		return this.addValidator({
+			message: (_, label, message) => `${message.replace('Expected', 'Expected property')} in ${label}`,
+			validator: object => exact(object, shape)
+		});
+	}
 }

test/array.ts

@@ -168,3 +168,21 @@ test('array.ofType', t => {
 		ow(['foo', 'b'], 'foo', ow.array.ofType(ow.string.minLength(3)));
 	}, '(array `foo`) Expected string to have a minimum length of `3`, got `b`');
 });
+
+test('array.exactShape', t => {
+	t.notThrows(() => {
+		ow(['🦄', 2, 3, true, {isFirstCommit: true}], ow.array.exactShape([ow.string, ow.number, ow.number, ow.boolean, ow.object.exactShape({isFirstCommit: ow.boolean})]));
+	});
+
+	t.throws(() => {
+		ow(['🦄', 2, 'nope', true, {isFirstCommit: true}], ow.array.exactShape([ow.string, ow.number, ow.number, ow.boolean, ow.object.exactShape({isFirstCommit: ow.string})]));
+	}, 'Expected property `2` to be of type `number` but received type `string` in array');
+
+	t.throws(() => {
+		ow(['🦄', 'nope', {isFirstCommit: true}], ow.array.exactShape([ow.string, ow.string, ow.object.exactShape({isFirstCommit: ow.boolean}), ow.number, ow.boolean]));
+	}, 'Expected property `3` to be of type `number` but received type `undefined` in array');
+
+	t.throws(() => {
+		ow(['🦄', {isFirstCommit: true}, 'nope', 5, {accepted: false}], ow.array.exactShape([ow.string, ow.object.exactShape({isFirstCommit: ow.boolean}), ow.string]));
+	}, 'Did not expect property `3` to exist, got `5` in array');
+});