test.linkheader.js

/**
* @license Apache-2.0
*
* Copyright (c) 2026 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 parseLinkHeader = require( './../lib/linkheader.js' );


// TESTS //

tape( 'main export is a function', function test( t ) {
	t.ok( true, __filename );
	t.strictEqual( typeof parseLinkHeader, 'function', 'main export is a function' );
	t.end();
});

tape( 'the function returns `null` if provided an empty header', function test( t ) {
	t.strictEqual( parseLinkHeader( '' ), null, 'returns expected value' );
	t.end();
});

tape( 'the function returns `null` if provided a malformed header', function test( t ) {
	t.strictEqual( parseLinkHeader( 'beep; boop' ), null, 'returns expected value' );
	t.end();
});

tape( 'the function returns `null` if provided a header exceeding the maximum length', function test( t ) {
	var header;
	var tail;
	var i;

	header = '<https://api.github.com/user/9287/repos?page=2&per_page=1>; rel="next", ';
	tail = '';
	for ( i = 0; i < 2100; i++ ) {
		tail += 'a';
	}
	header += tail;

	t.strictEqual( header.length > 2000, true, 'test fixture exceeds maximum length' );
	t.strictEqual( parseLinkHeader( header ), null, 'returns expected value' );
	t.end();
});

tape( 'the function parses paginated GitHub link headers', function test( t ) {
	var header;
	var out;

	header = '<https://api.github.com/user/9287/repos?page=2&per_page=1>; rel="next", <https://api.github.com/user/9287/repos?page=3&per_page=1>; rel="last"';
	out = parseLinkHeader( header );

	t.deepEqual( out, {
		'next': {
			'url': 'https://api.github.com/user/9287/repos?page=2&per_page=1',
			'page': '2',
			'per_page': '1',
			'rel': 'next'
		},
		'last': {
			'url': 'https://api.github.com/user/9287/repos?page=3&per_page=1',
			'page': '3',
			'per_page': '1',
			'rel': 'last'
		}
	}, 'returns expected value' );
	t.end();
});

tape( 'the function supports multiple relation types for a single link value', function test( t ) {
	var header;
	var out;

	header = '<https://api.github.com/user/9287/repos?page=1>; rel="prev previous"';
	out = parseLinkHeader( header );

	t.strictEqual( out.prev, out.previous, 'relations reference the same value' );
	t.strictEqual( out.prev.page, '1', 'sets query parameter values' );
	t.strictEqual( out.prev.rel, 'prev previous', 'retains original relation string' );
	t.end();
});

tape( 'the function preserves additional link parameters', function test( t ) {
	var header;
	var out;

	header = '<https://api.github.com/user/9287/repos?page=2>; rel="next"; type="application/json"; title="next, page"';
	out = parseLinkHeader( header );

	t.strictEqual( out.next.type, 'application/json', 'sets the media type' );
	t.strictEqual( out.next.title, 'next, page', 'sets the title' );
	t.end();
});