join-url

join-url.js

import queryString from 'query-string';

const defaultUrlRegExp = /^(\w+:\/\/[^/?]+)?(.*?)(\?.+)?$/;
const protocolRelativeUrlRegExp = /^(\/\/[^/?]+)(.*?)(\?.+)?$/;

const normalizeParts = (parts) => (
    parts
    // Filter non-string or non-numeric values
    .filter((part) => typeof part === 'string' || typeof part === 'number')
    // Convert to strings
    .map((part) => `${part}`)
    // Remove empty parts
    .filter((part) => part)
);

const parseParts = (parts, options) => {
    const { protocolRelative } = options;

    const partsStr = parts.join('/');
    const urlRegExp = protocolRelative ? protocolRelativeUrlRegExp : defaultUrlRegExp;
    const [, prefix = '', pathname = '', suffix = ''] = partsStr.match(urlRegExp) || [];

    return {
        prefix,
        pathname: {
            parts: pathname.split('/').filter((part) => part !== ''),
            hasLeading: suffix ? /^\/\/+/.test(pathname) : /^\/+/.test(pathname),
            hasTrailing: suffix ? /\/\/+$/.test(pathname) : /\/+$/.test(pathname),
        },
        suffix,
    };
};

const buildUrl = (parsedParts, options) => {
    const { prefix, pathname, suffix } = parsedParts;
    const { parts: pathnameParts, hasLeading, hasTrailing } = pathname;
    const { leadingSlash, trailingSlash } = options;

    const addLeading = leadingSlash === true || (leadingSlash === 'keep' && hasLeading);
    const addTrailing = trailingSlash === true || (trailingSlash === 'keep' && hasTrailing);

    // Start with prefix if not empty (http://google.com)
    let url = prefix;

    // Add the parts
    if (pathnameParts.length > 0) {
        url += url || addLeading ? '/' : '';
        url += pathnameParts.join('/');
    }

    // Add trailing to the end
    if (addTrailing) {
        url += '/';
    }

    // Add leading if URL is still empty
    if (!url && addLeading) {
        url += '/';
    }

    // Build a query object based on the url query string and options query object
    const query = { ...queryString.parse(suffix, options.queryOptions), ...options.query };
    const queryStr = queryString.stringify(query, options.queryOptions);

    if (queryStr) {
        url += `?${queryStr}`;
    }

    return url;
};

const urlJoin = (...parts) => {
    const lastArg = parts[parts.length - 1];
    let options;

    // If last argument is an object, then it's the options
    // Note that null is an object, so we verify if is truthy
    if (lastArg && typeof lastArg === 'object') {
        options = lastArg;
        parts = parts.slice(0, -1);
    }

    // Parse options
    options = {
        leadingSlash: true,
        trailingSlash: false,
        protocolRelative: false,
        ...options,
    };

    // Normalize parts before parsing them
    parts = normalizeParts(parts);

    // Split the parts into prefix, pathname, and suffix
    // (scheme://host)(/pathnameParts.join('/'))(?queryString)
    const parsedParts = parseParts(parts, options);

    // Finaly build the url based on the parsedParts
    return buildUrl(parsedParts, options);
};

export default urlJoin;

test.js

import urlJoin from '../src';

it('should add leading slash and no trailing slash by default', () => {
    expect(urlJoin()).toBe('/');
    expect(urlJoin(undefined, 'foo')).toBe('/foo');
    expect(urlJoin('foo', null, 'bar')).toBe('/foo/bar');
    expect(urlJoin('foo', '', 'bar')).toBe('/foo/bar');
    expect(urlJoin('foo')).toBe('/foo');
    expect(urlJoin('/foo')).toBe('/foo');
    expect(urlJoin('/', '/foo')).toBe('/foo');
    expect(urlJoin('/', '//foo')).toBe('/foo');
    expect(urlJoin('/', '/foo//')).toBe('/foo');
    expect(urlJoin('/', '/foo/', '')).toBe('/foo');
    expect(urlJoin('/', '/foo/', '/')).toBe('/foo');
    expect(urlJoin('foo', 'bar')).toBe('/foo/bar');
    expect(urlJoin('/foo', 'bar')).toBe('/foo/bar');
    expect(urlJoin('/foo', '/bar')).toBe('/foo/bar');
    expect(urlJoin('/foo/', '/bar/')).toBe('/foo/bar');
    expect(urlJoin('/foo/', '/bar/baz')).toBe('/foo/bar/baz');
    expect(urlJoin('/foo/', '/bar//baz')).toBe('/foo/bar/baz');

    expect(urlJoin('http://google.com')).toBe('http://google.com');
    expect(urlJoin('http://google.com/')).toBe('http://google.com');
    expect(urlJoin('http://google.com', '')).toBe('http://google.com');
    expect(urlJoin('http://google.com', 'foo')).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', 'foo')).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', '/foo')).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com//', '/foo')).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/foo', 'bar')).toBe('http://google.com/foo/bar');

    expect(urlJoin('http://google.com', '?queryString')).toBe('http://google.com?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString')).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString')).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString')).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com?queryString')).toBe('http://google.com?queryString');
});

it('should add leading slash and trailing slash', () => {
    const options = { trailingSlash: true };

    expect(urlJoin(options)).toBe('/');
    expect(urlJoin(undefined, 'foo', options)).toBe('/foo/');
    expect(urlJoin('foo', null, 'bar', options)).toBe('/foo/bar/');
    expect(urlJoin('foo', '', 'bar', options)).toBe('/foo/bar/');
    expect(urlJoin('foo', options)).toBe('/foo/');
    expect(urlJoin('/foo', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo', options)).toBe('/foo/');
    expect(urlJoin('/', '//foo', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo//', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo/', '', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('/foo/');
    expect(urlJoin('foo', 'bar', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo', 'bar', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo', '/bar', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('/foo/bar/baz/');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('/foo/bar/baz/');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar/');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com/?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com?queryString', options)).toBe('http://google.com/?queryString');
});

it('should remove leading slash and add trailing slash', () => {
    const options = { leadingSlash: false, trailingSlash: true };

    expect(urlJoin(options)).toBe('/');
    expect(urlJoin(undefined, 'foo', options)).toBe('foo/');
    expect(urlJoin('foo', null, 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('foo', '', 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('foo', options)).toBe('foo/');
    expect(urlJoin('/foo', options)).toBe('foo/');
    expect(urlJoin('/', '/foo', options)).toBe('foo/');
    expect(urlJoin('/', '//foo', options)).toBe('foo/');
    expect(urlJoin('/', '/foo//', options)).toBe('foo/');
    expect(urlJoin('/', '/foo/', '', options)).toBe('foo/');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('foo/');
    expect(urlJoin('foo', 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('/foo', 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('/foo', '/bar', options)).toBe('foo/bar/');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('foo/bar/');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('foo/bar/baz/');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('foo/bar/baz/');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar/');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com/?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com?queryString', options)).toBe('http://google.com/?queryString');
});

it('should remove leading slash and trailing slash', () => {
    const options = { leadingSlash: false, trailingSlash: false };

    expect(urlJoin(options)).toBe('');
    expect(urlJoin(undefined, 'foo', options)).toBe('foo');
    expect(urlJoin('foo', null, 'bar', options)).toBe('foo/bar');
    expect(urlJoin('foo', '', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('foo', options)).toBe('foo');
    expect(urlJoin('/foo', options)).toBe('foo');
    expect(urlJoin('/', '/foo', options)).toBe('foo');
    expect(urlJoin('/', '//foo', options)).toBe('foo');
    expect(urlJoin('/', '/foo//', options)).toBe('foo');
    expect(urlJoin('/', '/foo/', '', options)).toBe('foo');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('foo');
    expect(urlJoin('foo', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo', '/bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('foo/bar');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('foo/bar/baz');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('foo/bar/baz');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com?queryString', options)).toBe('http://google.com?queryString');
});

it('should support URLs with relative protocol according to options.protocolRelative', () => {
    const options = { protocolRelative: true };

    expect(urlJoin('//google.com', 'foo', options)).toBe('//google.com/foo');
    expect(urlJoin('//google.com/', 'foo', options)).toBe('//google.com/foo');
    expect(urlJoin('//google.com/foo', 'bar', options)).toBe('//google.com/foo/bar');
    expect(urlJoin('//google.com/foo//', 'bar', options)).toBe('//google.com/foo/bar');

    options.protocolRelative = false;

    expect(urlJoin('//google.com', 'foo', options)).toBe('/google.com/foo');
    expect(urlJoin('//google.com/', 'foo', options)).toBe('/google.com/foo');
    expect(urlJoin('//google.com/foo', 'bar', options)).toBe('/google.com/foo/bar');
    expect(urlJoin('//google.com/foo//', 'bar', options)).toBe('/google.com/foo/bar');
});

it('should include numbers', () => {
    expect(urlJoin(undefined, 1)).toBe('/1');
    expect(urlJoin(1, null, 2)).toBe('/1/2');
    expect(urlJoin(1, '', 2)).toBe('/1/2');
    expect(urlJoin(1)).toBe('/1');
    expect(urlJoin('/1')).toBe('/1');
    expect(urlJoin('/', '/1')).toBe('/1');
    expect(urlJoin('/', '//1')).toBe('/1');
    expect(urlJoin('/', '/1//')).toBe('/1');
    expect(urlJoin('/', '/1/', '')).toBe('/1');
    expect(urlJoin('/', '/1/', '/')).toBe('/1');
    expect(urlJoin(1, 2)).toBe('/1/2');
    expect(urlJoin('/1', 2)).toBe('/1/2');
    expect(urlJoin('/1', '/2')).toBe('/1/2');
    expect(urlJoin('/1/', '/2/')).toBe('/1/2');
    expect(urlJoin('/1/', '/2/3')).toBe('/1/2/3');
    expect(urlJoin('/1/', '/2//3')).toBe('/1/2/3');

    expect(urlJoin('http://google.com', 1)).toBe('http://google.com/1');
    expect(urlJoin('http://google.com/', 1)).toBe('http://google.com/1');
    expect(urlJoin('http://google.com/', '/1')).toBe('http://google.com/1');
    expect(urlJoin('http://google.com//', '/1')).toBe('http://google.com/1');
    expect(urlJoin('http://google.com/1', 2)).toBe('http://google.com/1/2');

    expect(urlJoin('http://google.com', '?1')).toBe('http://google.com?1');
    expect(urlJoin('http://google.com', 'foo?1')).toBe('http://google.com/foo?1');
    expect(urlJoin('http://google.com', 'foo', '?1')).toBe('http://google.com/foo?1');
    expect(urlJoin('http://google.com', 'foo/', '?1')).toBe('http://google.com/foo?1');
    expect(urlJoin('http://google.com?1')).toBe('http://google.com?1');
});

it('should handle the provided query object and append it to the url', () => {
    const options = { query: { biz: 'buz', foo: 'bar' } };

    expect(urlJoin('/google.com', options)).toBe('/google.com?biz=buz&foo=bar');
    expect(urlJoin('google.com', options)).toBe('/google.com?biz=buz&foo=bar');

    options.protocolRelative = false;

    expect(urlJoin('//google.com', options)).toBe('/google.com?biz=buz&foo=bar');

    options.leadingSlash = false;

    expect(urlJoin('google.com', options)).toBe('google.com?biz=buz&foo=bar');

    options.trailingSlash = true;

    expect(urlJoin('google.com', options)).toBe('google.com/?biz=buz&foo=bar');

    options.trailingSlash = false;

    expect(urlJoin('google.com', 'qux?tux=baz', options)).toBe('google.com/qux?biz=buz&foo=bar&tux=baz');
});

it('should handle the provided query and query options objects', () => {
    const options = { query: { foo: [1, 2, 3] }, queryOptions: {} };

    expect(urlJoin('/google.com', options)).toBe('/google.com?foo=1&foo=2&foo=3');

    options.queryOptions.arrayFormat = 'bracket';

    expect(urlJoin('/google.com', options)).toBe('/google.com?foo[]=1&foo[]=2&foo[]=3');

    options.queryOptions.arrayFormat = 'index';

    expect(urlJoin('/google.com', options)).toBe('/google.com?foo[0]=1&foo[1]=2&foo[2]=3');
});

it('should keep leading slash and remove trailing slash', () => {
    const options = { leadingSlash: 'keep' };

    expect(urlJoin(options)).toBe('');
    expect(urlJoin(undefined, 'foo', options)).toBe('foo');
    expect(urlJoin('foo', null, 'bar', options)).toBe('foo/bar');
    expect(urlJoin('foo', '', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('foo', options)).toBe('foo');
    expect(urlJoin('/foo', options)).toBe('/foo');
    expect(urlJoin('/', '/foo', options)).toBe('/foo');
    expect(urlJoin('/', '//foo', options)).toBe('/foo');
    expect(urlJoin('/', '/foo//', options)).toBe('/foo');
    expect(urlJoin('/', '/foo/', '', options)).toBe('/foo');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('/foo');
    expect(urlJoin('foo', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo', 'bar', options)).toBe('/foo/bar');
    expect(urlJoin('/foo', '/bar', options)).toBe('/foo/bar');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('/foo/bar');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('/foo/bar/baz');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('/foo/bar/baz');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo?queryString');
});

it('should add leading slash and keep trailing slash', () => {
    const options = { trailingSlash: 'keep' };

    expect(urlJoin(options)).toBe('/');
    expect(urlJoin(undefined, 'foo', options)).toBe('/foo');
    expect(urlJoin('foo', null, 'bar', options)).toBe('/foo/bar');
    expect(urlJoin('foo', '', 'bar', options)).toBe('/foo/bar');
    expect(urlJoin('foo', options)).toBe('/foo');
    expect(urlJoin('/foo', options)).toBe('/foo');
    expect(urlJoin('/', '/foo', options)).toBe('/foo');
    expect(urlJoin('/', '//foo', options)).toBe('/foo');
    expect(urlJoin('/', '/foo//', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo/', '', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('/foo/');
    expect(urlJoin('foo', 'bar', options)).toBe('/foo/bar');
    expect(urlJoin('/foo', 'bar', options)).toBe('/foo/bar');
    expect(urlJoin('/foo', '/bar', options)).toBe('/foo/bar');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('/foo/bar/baz');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('/foo/bar/baz');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo/?queryString');
});

it('should keep leading slash and add trailing slash', () => {
    const options = { leadingSlash: 'keep', trailingSlash: true };

    expect(urlJoin(options)).toBe('/');
    expect(urlJoin(undefined, 'foo', options)).toBe('foo/');
    expect(urlJoin('foo', null, 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('foo', '', 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('foo', options)).toBe('foo/');
    expect(urlJoin('/foo', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo', options)).toBe('/foo/');
    expect(urlJoin('/', '//foo', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo//', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo/', '', options)).toBe('/foo/');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('/foo/');
    expect(urlJoin('foo', 'bar', options)).toBe('foo/bar/');
    expect(urlJoin('/foo', 'bar', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo', '/bar', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('/foo/bar/');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('/foo/bar/baz/');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('/foo/bar/baz/');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com/');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo/');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar/');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com/?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com?queryString', options)).toBe('http://google.com/?queryString');
});

it('should remove leading slash and keep trailing slash', () => {
    const options = { leadingSlash: false, trailingSlash: 'keep' };

    expect(urlJoin(options)).toBe('');
    expect(urlJoin(undefined, 'foo', options)).toBe('foo');
    expect(urlJoin('foo', null, 'bar', options)).toBe('foo/bar');
    expect(urlJoin('foo', '', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('foo', options)).toBe('foo');
    expect(urlJoin('/foo', options)).toBe('foo');
    expect(urlJoin('/', '/foo', options)).toBe('foo');
    expect(urlJoin('/', '//foo', options)).toBe('foo');
    expect(urlJoin('/', '/foo//', options)).toBe('foo/');
    expect(urlJoin('/', '/foo/', '', options)).toBe('foo/');
    expect(urlJoin('/', '/foo/', '/', options)).toBe('foo/');
    expect(urlJoin('foo', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo', 'bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo', '/bar', options)).toBe('foo/bar');
    expect(urlJoin('/foo/', '/bar/', options)).toBe('foo/bar/');
    expect(urlJoin('/foo/', '/bar/baz', options)).toBe('foo/bar/baz');
    expect(urlJoin('/foo/', '/bar//baz', options)).toBe('foo/bar/baz');

    expect(urlJoin('http://google.com', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com/', options)).toBe('http://google.com/');

    expect(urlJoin('http://google.com', '', options)).toBe('http://google.com');
    expect(urlJoin('http://google.com', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', 'foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com//', '/foo', options)).toBe('http://google.com/foo');
    expect(urlJoin('http://google.com/foo', 'bar', options)).toBe('http://google.com/foo/bar');

    expect(urlJoin('http://google.com', '?queryString', options)).toBe('http://google.com?queryString');
    expect(urlJoin('http://google.com', 'foo?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo', '?queryString', options)).toBe('http://google.com/foo?queryString');
    expect(urlJoin('http://google.com', 'foo/', '?queryString', options)).toBe('http://google.com/foo/?queryString');
    expect(urlJoin('http://google.com?queryString', options)).toBe('http://google.com?queryString');
});