myRouter.module.ts (extract)

const appRoutes: Routes = [
    {
        path:      '',
        component: HomepageComponent,
    },
    {
        matcher:   UrlMatcher,
        component: ProductComponent,
    },
    {
        path:      '**',
        component: Error404Component,
    },
];          

urlMatcher.ts

import { UrlMatchResult, UrlSegment } from '@angular/router';

export function UrlMatcher(url: UrlSegment[], regex: RegExp, capturedParameterNames: string[]): urlMatchResult | null {
    if (url.length === 0) {
        return null;
    }

    capturedParameterNames.splice(0, 0, 'fullPath');

    let fullPath = '';
    let result: RegExpExecArray | null;
    for (let i = 0; i < url.length; ++i) {
        if (url[i].path) {
            fullPath += '/' + url[i].path;
        }
    }

    if (result = regex.exec(fullPath)) {
        const posParams: {[p: string]: UrlSegment} = {};
        for (let index = 0; index < result.length; index++) {
            posParams[capturedParameterNames[index]] = new UrlSegment(result[index], {});
        }
        return {consumed: url, posParams: posParams};
    }

    return null;
}

For mine use case where a matcher can have optionally parameter

/**
 * Generic matcher function
 *
 * Set in route data variable with a named regex to get parameters
 * ie:
 * data: {
 *     regex: /^(?<currency_pair>[a-z_]{3,6}-[a-z_]{3,6})?$/
 * }
 */
export function matcher(segments: UrlSegment[], segmentGroup: UrlSegmentGroup, route: Route): UrlMatchResult {
    const regex = route.data.regex;
    const url = segments.length == 1 ? segments[0].toString() : '';

    let params = url.match(regex);
    if (params) {
        const posParams: { [key: string]: UrlSegment } = {};

        // Named parameter based in name group of regexp
        for (const [name, value] of Object.entries(params.groups)) {
            posParams[name] = new UrlSegment(value, {});;
        }

        return { consumed: segments, posParams };
    }

    return null;
}