test: add tests for slice method in dstructs/named-typed-tuple

lib/node_modules/@stdlib/dstructs/named-typed-tuple/test/test.slice.js

@@ -0,0 +1,300 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var tape = require( 'tape' );
+var hasOwnProp = require( '@stdlib/assert/has-own-property' );
+var isFunction = require( '@stdlib/assert/is-function' );
+var namedtypedtuple = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+	t.ok( true, __filename );
+	t.strictEqual( typeof namedtypedtuple, 'function', 'main export is a function' );
+	t.end();
+});
+
+tape( 'a tuple has a `slice` method', function test( t ) {
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y' ], {
+		'name': 'Point'
+	});
+	p = new Point( [ 10, 20 ] );
+
+	t.strictEqual( hasOwnProp( p, 'slice' ), true, 'returns expected value' );
+	t.strictEqual( isFunction( p.slice ), true, 'returns expected value' );
+	t.end();
+});
+
+tape( 'the method throws an error if invoked with a `this` context which is not a namedtypedtuple instance', function test( t ) {
+	var values;
+	var Point;
+	var p;
+	var i;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z' ] );
+	p = new Point( [ 10, 20, 30 ] );
+
+	values = [
+		'5',
+		5,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[],
+		function noop() {}
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[i] ), TypeError, 'throws an error when provided '+values[i] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			return p.slice.call( value );
+		};
+	}
+});
+
+tape( 'the method throws an error if provided a first argument which is not an integer', function test( t ) {
+	var values;
+	var Point;
+	var p;
+	var i;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z' ] );
+	p = new Point( [ 10, 20, 30 ] );
+
+	values = [
+		'5',
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[]
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[i] ), TypeError, 'throws an error when provided '+values[i] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			return p.slice( value );
+		};
+	}
+});
+
+tape( 'the method throws an error if provided a second argument which is not an integer', function test( t ) {
+	var values;
+	var Point;
+	var p;
+	var i;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z' ] );
+	p = new Point( [ 10, 20, 30 ] );
+
+	values = [
+		'5',
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[]
+	];
+	for ( i = 0; i < values.length; i++ ) {
+		t.throws( badValue( values[i] ), TypeError, 'throws an error when provided '+values[i] );
+	}
+	t.end();
+
+	function badValue( value ) {
+		return function badValue() {
+			return p.slice( 0, value );
+		};
+	}
+});
+
+tape( 'if called without arguments, the method returns a tuple containing the same elements as the original tuple', function test( t ) {
+	var expected;
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z' ] );
+	p = new Point( [ 10, 20, 30 ] );
+	expected = {
+		'x': 10,
+		'y': 20,
+		'z': 30
+	};
+	actual = p.slice();
+
+	t.deepEqual({
+		'x': actual.x,
+		'y': actual.y,
+		'z': actual.z
+	}, expected, 'returns expected value' );
+	t.notEqual( actual, p, 'returns a new instance' );
+	t.end();
+});
+
+tape( 'if called with one argument, the method returns a tuple containing elements starting from a specified beginning index (inclusive)', function test( t ) {
+	var expected;
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z', 'w' ] );
+	p = new Point( [ 1, 2, 3, 4 ] );
+	expected = {
+		'y': 2,
+		'z': 3,
+		'w': 4
+	};
+	actual = p.slice( 1 );
+
+	t.deepEqual({
+		'y': actual.y,
+		'z': actual.z,
+		'w': actual.w
+	}, expected, 'returns expected value' );
+	t.end();
+});
+
+tape( 'if provided two arguments, the method returns a tuple containing elements starting from a specified start index (inclusive) and ending at a specified end index (exclusive)', function test( t ) {
+	var expected;
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z', 'w' ] );
+	p = new Point( [ 1, 2, 3, 4 ] );
+	expected = {
+		'y': 2,
+		'z': 3
+	};
+	actual = p.slice( 1, 3 );
+
+	t.deepEqual({
+		'y': actual.y,
+		'z': actual.z
+	}, expected, 'returns expected value' );
+
+	expected = {
+		'y': 2,
+		'z': 3,
+		'w': 4
+	};
+	actual = p.slice( 1, 30 );
+
+	t.deepEqual({
+		'y': actual.y,
+		'z': actual.z,
+		'w': actual.w
+	}, expected, 'returns expected value' );
+	t.end();
+});
+
+tape( 'the method resolves negative indices relative to the last element', function test( t ) {
+	var expected;
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z', 'w' ] );
+	p = new Point( [ 1, 2, 3, 4 ] );
+
+	expected = {
+		'y': 2,
+		'z': 3
+	};
+	actual = p.slice( -3, -1 );
+	t.deepEqual({
+		'y': actual.y,
+		'z': actual.z
+	}, expected, 'returns expected value' );
+
+	expected = {
+		'x': 1,
+		'y': 2
+	};
+	actual = p.slice( -30, -2 );
+	t.deepEqual({
+		'x': actual.x,
+		'y': actual.y
+	}, expected, 'returns expected value' );
+	t.end();
+});
+
+tape( 'the method returns null if a resolved beginning index exceeds a resolved ending index', function test( t ) {
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z', 'w' ] );
+	p = new Point( [ 1, 2, 3, 4 ] );
+	actual = p.slice( 2, 0 );
+
+	t.strictEqual( actual, null, 'returns expected value' );
+	t.end();
+});
+
+tape( 'the method returns null if a resolved beginning index exceeds the maximum tuple index', function test( t ) {
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z' ] );
+	p = new Point( [ 1, 2, 3 ] );
+	actual = p.slice( 5 );
+
+	t.strictEqual( actual, null, 'returns expected value' );
+	t.end();
+});
+
+tape( 'the method returns null if a resolved ending index is less than or equal to zero', function test( t ) {
+	var actual;
+	var Point;
+	var p;
+
+	Point = namedtypedtuple( [ 'x', 'y', 'z', 'w' ] );
+	p = new Point( [ 1, 2, 3, 4 ] );
+
+	actual = p.slice( 2, -8 );
+	t.strictEqual( actual, null, 'returns expected value' );
+
+	actual = p.slice( 1, 0 );
+	t.strictEqual( actual, null, 'returns expected value' );
+	t.end();
+});