cranker-router/mapping.js

A cranker router in Javascript.

// How router path mapping works - see the test-mapping.js file

const longestPathFirst = function (path) {
    return path
        .substring(1)
        .split("/")
        .reverse()
        .reduce((a,o,i,arr) => {
            const targetPath = arr.slice(i).reverse().join("/");
            if (i === arr.length - 1 && targetPath === "") {
                return a;
            }
            return a.concat([targetPath]);
        }, [])
        .concat(["/"]);
};

const pathMatch = function (path, routeList, next) {
    const candidateMatchPaths = path === "/" ? [path] : longestPathFirst(path);
    if (candidateMatchPaths === null) {
        return next();
    }

    let routePath;
    let wsList;
    
    for (const routablePath of candidateMatchPaths) {
        const matchedPath = Object.keys(routeList) // Find the longest path with an indexOf match
              .filter(route => route.indexOf(routablePath) === 0)
              .map(route => [route, route.length])
              .sort(([pathA, lenA], [pathB, lenB]) => lenA < lenB ? -1 : lenA > lenB ? 1 : 0)
              .reverse()
              .slice(0,1)
              .map(([path, len]) => path);
        
        if (matchedPath !== undefined || matchedPath.length === 1) {
            routePath = matchedPath[0];
            wsList = routeList[routePath];
            if (wsList !== undefined) {
                break;
            }
        }
    }

    return {routePath, wsList};
};

exports.longestPathFirst = longestPathFirst;
exports.pathMatch = pathMatch;

// End