api-router-library.js

import http from "http";

const db = createDb();
const app = createApp();
const router = app()
  .on("GET", "/api/score", function(req, res) {
    result(res, 200, { scores: db.entries() });
  })
  .on("POST", "/api/score", function(req, res) {
    const { name, score } = req.body;
    if (!name || !score) {
      return result(res, 400, { message: "Bad request" });
    }
    result(res, 200, db.insert(name, score));
  })
  .on("GET", /\/api\/score\/(?<id>\w+)/, function(req, res) {
    const score = db.get(req.params.id);
    if (!score) {
      return result(res, 404, { message: "Not found" });
    }

    result(res, 200, score);
  })
  .on("DELETE", /\/api\/score\/(?<id>\w+)/, function(req, res) {
    const score = db.delete(req.params.id);
    if (!score) {
      return result(res, 400, { message: "Bad Request" });
    }
    result(res, 200, { message: "ok" });
  })
  .on("PUT", /\/api\/score\/(?<id>\w+)/, function(req, res) {
    const { name, score } = req.body;
    if (!name || !score) {
      return result(res, 400, { message: "Bad request" });
    }
    const scoreItem = db.update(req.params.id, name, score);
    if (!scoreItem) {
      return result(res, 404, { message: "Not found" });
    }
    result(res, 200, scoreItem);
  })
  .fallback(function(_, res) {
    result(res, 404, { message: "Not found" });
  });

const server = http.createServer(router.handle);

const port = process.env.PORT || 3001;
server.listen(port, function() {
  console.log(`Now listening to http://localhost:${port}`);
});

// Library implementation

// Own module, just as function here.
function createApp() {
  return function app(routes = []) {
    return {
      on(method, path, cb) {
        return app(
          routes.concat({
            method,
            path,
            cb
          })
        );
      },

      fallback(cb) {
        return app(
          routes.concat({
            fallback: true,
            method: "-",
            path: "-",
            cb
          })
        );
      },

      async handle(req, res) {
        for (let { method, path, cb } of routes) {
          if (
            !isMethodMatch(req.method, method) ||
            !isRouteMatch(req.url, path)
          ) {
            continue;
          }

          req.body = await bufferData(req);
          req.params = getParams(req.url, path);
          return cb(req, res);
        }

        const noHit = routes.find(i => i.fallback);
        if (noHit) {
          return noHit.cb(req, res);
        }

        result(res, 400, { message: "Bad request" });
      }
    };
  };

  function isMethodMatch(sMethod, pMethod) {
    return sMethod.toLowerCase() === pMethod.toLowerCase() || pMethod === "*";
  }

  function isRouteMatch(path, pattern) {
    if (typeof pattern === "string") {
      return path.toLowerCase() === pattern.toLowerCase();
    }
    if (pattern instanceof RegExp) {
      return pattern.exec(path) !== null;
    }
    return false;
  }

  function getParams(path, pattern) {
    if (pattern instanceof RegExp) {
      const match = pattern.exec(path);
      return match.groups || {};
    }
    return {};
  }

  async function bufferData(req) {
    return new Promise(function(res, rej) {
      let data = [];
      req.on("data", chunk => {
        data.push(chunk);
      });

      req.on("end", () => {
        if (!data.length) {
          res({});
        } else {
          res(JSON.parse(data));
        }
      });
    });
  }
}

function result(res, status, body) {
  const data = JSON.stringify(body);
  return res
    .writeHead(status, {
      "Content-Length": Buffer.byteLength(data),
      "Content-Type": "application/json"
    })
    .end(data);
}

// Own module also, but yeah.
function createDb() {
  let scoresData = {
    0: {
      id: 0,
      name: "foo@dsa.com",
      score: 3000,
      timestamp: new Date()
    },
    1: {
      id: 1,
      name: "bar@dsa.com",
      score: 2000,
      timestamp: new Date()
    }
  };

  function rand() {
    return Math.random()
      .toString(36)
      .replace(/[^a-z]+/g, "")
      .substr(2, 10);
  }

  return {
    entries() {
      return Object.values(scoresData);
    },
    get(id) {
      return scoresData[id];
    },
    insert(name, score) {
      const id = rand();
      const newObj = {
        name,
        score,
        id
      };
      scoresData[id] = newObj;
      return newObj;
    },
    delete(id) {
      const score = scoresData[id];
      if (!score) return false;
      delete scoresData[id];
      return true;
    },
    update(id, name, score) {
      const scoreItem = scoresData[id];
      if (!scoreItem) return false;

      const newObj = {
        ...scoreItem,
        name,
        score
      };

      scoresData[id] = newObj;
      return newObj;
    }
  };
}