file-routing-expressjs

A dependency-free, flexible, system-based file routing for Express.

Installation

npm install file-routing-expressjs

Usage

This package integration in your project is very simple. You will need to wrap your Express instance with an mapRoutes(config) that will bind the routes directly to the app.

import express from "express";
import path from "path";
import { mapRoutes, errorGuardMiddleware } from "file-routing-expressjs";

const ROUTES_PATH = path.resolve(__dirname, "..", "app", "routes");

const app = express();

// Option 1: Basic usage
mapRoutes({
    app: app,
    target: ROUTES_PATH,
    errorGuard: true // ✅ Enable automatic async error wrapping
});

// Option 2: Using a custom error guard middleware
mapRoutes({
    app: app,
    target: ROUTES_PATH,
    errorGuard: errorGuardMiddleware // ✅ Pass your own error guard logic
});

// Option 3: If you need to log the endpoints
async function main() {
    const { endpoints } = await mapRoutes({
        app: app,
        target: ROUTES_PATH,
        errorGuard: true
    });
    console.table(endpoints);
}

main();

app.listen(3000, ()=> console.log("I'm listening mother father"));

Options

• target: The root directory for your route files. Defaults to /src/routes.
• app: The instance of the Express application used for handling routes.
• errorGuard: This prevents the need to manually wrap every async handler with try/catch.

Routes Directory Structure

Files located in your project's options.target directory will automatically correspond to a matching URL path.

Note: Files that start with an underscore (_) or do not have a .ts or .js extension will not be bound to the app.

📦routes  
 ┣ 📂api  
 ┃ ┗ 📜index.ts
 ┃ ┗ 📜_middleware.ts # global middlewares for '/api' 
 ┣ 📂[users] # dynamic params 
 ┃ ┣ 📂[user]
 ┃ ┃ ┣ 📜index.ts  
 ┃ ┣ 📜books.ts  
 ┃ ┣ 📜index.ts
 ┃ ┣ 📜_middleware.ts
 ┃ ┣ 📜_error.ts
 ┃ ┗ 📜_config.ts # /:users config file (path pattern etc.)
 ┣ 📜index.ts # '/' endpoint - default route
 ┣ 📜posts.ts # '/posts' endpoint
 ┣ 📜_error.ts # global error handler

The folder structure is quite simple and straightforward, as you can see. 💀💀💀

• /api/<?pattern_in_index>
• /:users<?patter_in_config>/<?pattern_in_index>
• /:users<?patter_in_config>/books<?pattern_in_books>
• /:users<?patter_in_config>/:user/<?pattern_in_index>
• /<?pattern_in_index>
• /posts<?pattern_in_posts>

🔐 Error Guard Option

What is errorGuard?

• If enabled (true), it automatically wraps all your route handlers and middlewares with an async error handler.
• Any unhandled promise rejection inside async handlers will be forwarded to Express's error handlers (.use((err, req, res, next) => {})).
• This prevents the need to manually wrap every async handler with try/catch.

✅ Options

| Option | Type | Description | | -------------| ------------------------------------------| ----------------------------------------------------------------| | errorGuard | boolean or errorGuardMiddleware | Whether to auto-wrap handlers with async error catcher. Defaults to false. |

🚫 Example Without Error Guard

export const _get = async (req, res) => {
    const data = await fetchData(); // ❌ If fetchData throws, Express crashes
    res.json(data);
};

✅ Example With Error Guard (errorGuard: true)

Any async error in fetchData() will be passed to Express error handler (next(err)).

Examples

HTTP Method Handling

If you export functions such as get, post, put, patch, all or delete from a route file, they will automatically be mapped to their respective HTTP/Express methods .

export const _get = (req, res, next) => {...}
export const _post = (req, res) => {...}
export const _delete = (req, res) => {...}
export const _put = (req, res, next) => {...}
export const _patch = (req, res, next) => {...}
export const _all = (req, res, next) => {...}

Route Pattern

For a directory

In the example above, there's a file named /[users]/_config.ts. In this file, you should export an object that is used to configure the route pattern for that specific endpoint. This configuration object can include settings like a custom URL pattern or route validation.

// Option 1: default export
export default {
    pattern: /[a-fA-F0-9]{24}/g // this could be a Regex or a string 
};

// Option 2: named export
export const config = {
    pattern:'[a-fA-F0-9]{24}'
};

• /:users([a-fA-F0-9]{24})/<?pattern_in_index>

If users path is not a dynamic route your endpoint will be:

• /([a-fA-F0-9]{24})/<?pattern_in_index>

For JS/TS files

You can define a global pattern that applies to all HTTP methods in Express routes, or alternatively, specify a distinct pattern for each method within the route file. This allows for flexible URL handling, depending on whether you need a consistent format for all methods or different structures for specific HTTP methods.

// Option 1: a pattern for each method
export const config = {
    pattern: {
        get: /[A-Z]{3}-[0-9]{4}-[a-z]{2}/,
        post: /([0-9]{5})/,
        put: /[A-Z]{2}[0-9]{2}/
        delete: /(^\d{5}(-\d{4})?$)/,
        patch: /(^([01]\d|2[0-3]):([0-5]\d)$)/,
        all: /^\d{13,19}$/
    }
}

// Option 2: a global pattern 
export const config = {
    pattern: /[A-Z]{3}-[0-9]{4}-[a-z]{2}/
}

Option 1

| method | endpoint | | ---------- | --------------------------------------------------------- | | GET | /:users([a-fA-F0-9]{24})/([A-Z]{3}-[0-9]{4}-[a-z]{2}) | | POST | /:users([a-fA-F0-9]{24})/([0-9]{5}) | | PUT | /:users([a-fA-F0-9]{24})/([A-Z]{2}[0-9]{2}) | | DELETE | /:users([a-fA-F0-9]{24})/(^\d{5}(-\d{4})?$) | | PATCH | /:users([a-fA-F0-9]{24})/(^([01]\d\|2[0-3]):([0-5]\d)$) | | ALL | /:users([a-fA-F0-9]{24})/(^\d{13,19}$) |

Note: If you specify an all pattern in the configuration object, it will be used as the default pattern for any HTTP methods that are not explicitly defined.

Option 2

| method | endpoint | | ---------------------------------------------------------- | ------------------------------------------------------- | | GET, POST, PUT, DELETE, PATCH, ALL | /:users([a-fA-F0-9]{24})/([A-Z]{3}-[0-9]{4}-[a-z]{2}) |

Middleware

You can apply route-specific middleware in Express by exporting an array of request handlers directly from your route file.

For a directory

In the example above, there's a file named /[users]/_middleware.ts. In this file, you should export a middleware or the list of middlewares you want to apply on the endpoint (/users in this case). The middleware will wrap all the sub routes of /:users

import authMiddleware from "../middlewares/authMiddleware";
import rateLimitingMiddleware from "../middlewares/rateLimitingMiddleware";
import testMiddleware from "../middlewares/testMiddleware";

// Option 1: A list of middleware functions
export const middlewares = [
    authMiddleware,
	rateLimitingMiddleware
    testMiddleware
];

// Option 2: A single middlware function
export const middlewares = testMiddleware;

// default export or named export
export default middlewares;

For JS/TS files

You can define a global middleware/list of middlewares that wraps to all HTTP methods in Express routes, or alternatively, specify a distinct middleware/list of middlewares for each method within the route file.

// Option 1: One middleware for all the exisiting requests handlers
export const middlewares = authMiddleware;

// Option 2: A list of middlewares for all the exisiting requests handlers
export const middlewares = [rateLimitingMiddleware, authMiddleware, testMiddleware];

// Option 3: A map of methods with middlware/list of middlewares
export const middlewares = {
    get: [testMiddleware, rateLimitingMiddleware],
    all: authMiddleware
};

Note: Any route handlers that are not explicitly defined will be wrapped by the all middleware, if such middleware exists.

Error Handling

You can apply route-specific middleware in Express by exporting an array of request handlers directly from your route file.

For a directory

In the example above, there is a file named /[users]/_error_.ts. Within this file, you should export an error handler function, which can be either a default or named export. This function will handle errors specific to [users] directory route and the routes under it.

import globalErrorHandler from "../middlewares/globalErrorHandler";

export const errorHandler = globalErrorHandler;

// default export or named export
export default errorHandler;

For JS/TS files

You can define an error handler that wraps all HTTP methods in Express routes, or alternatively, specify a distinct error handler for each method within the route file.

import testErrorHandler from "../middlewares/testErrorHandler";
import clientErrorHandler from "../middlewares/clientErrorHandler";

// Option 1: A handler fro all the existing methods
export const error = clientErrorHandler;

// Option 2: A map of methods with error handlers
export const error = {
    put: testErrorHandler,
    all: clientErrorHandler
};

Note: Any route handlers that are not explicitly defined will be wrapped by the all error handler, if such error handler exists.

Examples - TS

For a directory

_config.ts

import { DirRouteConfig } from "file-routing-expressjs";
const config: DirRouteConfig = {
    pattern: "[A-Z]{2}-\\d{4}"
};

export default config;

_middleware.ts

import { RouterDirMiddleware } from "file-routing-expressjs";
import authMiddleware from "../middlewares/authMiddleware";
import testMiddleware from "../middlewares/testMiddleware";

export const middlewares: RouterDirMiddleware = [
    authMiddleware,
    testMiddleware
];

_error.ts

import { ErrorHandler } from "file-routing-expressjs";
import errorsMiddleware from "../middlewares/errorsMiddleware";

export const errorHandler: ErrorHandler = errorsMiddleware;

For JS/TS files

import { RequestHandler } from "express";
import { RouterFileMiddleware, RouterFileError, RouteConfig } from "file-routing-expressjs";
import testMiddleware from "../../middlewares/testMiddleware";
import authMiddleware from "../../middlewares/authMiddleware";
import clientErrorHandler from "../../middlewares/clientErrorMiddlware";

export const config: RouteConfig = {
    pattern: {
        get: /[A-Z]{3}-[0-9]{4}-[a-z]{2}/,
        all: /[a-fA-F0-9]{24}/
    }
};
export const middlewares: RouterFileMiddleware = {
    get: testMiddleware,
    all: authMiddleware
};
export const error: RouterFileError = clientErrorHandler;

export const _get: RequestHandler = (req, res, next)=> {...}
export const _post: RequestHandler = (req, res, next)=> {...}
export const _put: RequestHandler = (req, res, next)=> {...}

Plugins

Plugins allow you to wrap route handlers with reusable behaviors such as:

• caching
• retry logic
• circuit breakers
• timeouts
• logging
• rate limiting
• custom wrappers

Plugins are executed in the order defined by the developer.

⚠️ Execution Order

Plugin order matters.

export const config = {
    plugins: {
        get: {
            auth: true,
            cache: true,
            timeout: true
        }
    }
};

is NOT equivalent to:

export const config = {
    plugins: {
        get: {
            timeout: true,
            auth: true,
            cache: true
        }
    }
};

The framework does not reorder plugins automatically.

The developer is responsible for defining the correct order.

Plugin Registration

Plugins must first be registered globally through mapRoutes.

import cachePlugin from "./plugins/cachePlugin";
import timeoutPlugin from "./plugins/timeoutPlugin";
import retryPlugin from "./plugins/retryPlugin";

mapRoutes({
    app,
    target: ROUTES_PATH,

    plugins: [
        cachePlugin,
        timeoutPlugin,
        retryPlugin
    ]
});

For JS/TS files

Plugins are configured through the route config object.

export const config = {
    plugins: {
        get: {
            cache: true,

            timeout: {
                config: {
                    ms: 5000
                }
            }
        },

        post: {
            retry: {
                config: {
                    retries: 3,
                    delay: 1000
                }
            }
        },

        all: {
            "circuit-breaker": {
                enabled: true,

                config: {
                    threshold: 5,
                    cooldown: 10000
                }
            }
        }
    }
};

Plugin Options

Plugins support two declaration modes.

Boolean mode

cache: true

Enables the plugin with its default configuration.

Object mode

timeout: {
    enabled: true,

    config: {
        ms: 5000
    }
}

Allows enabling/disabling the plugin and passing custom configuration.

Built-in Plugins

Cache Plugin

Caches route responses in memory.

export const config = {
    plugins: {
        get: {
            cache: {
                config: {
                    ttl: 60000,
                    max: 100
                }
            }
        }
    }
};

Timeout Plugin

Cancels long-running requests.

export const config = {
    plugins: {
        get: {
            timeout: {
                config: {
                    ms: 5000
                }
            }
        }
    }
};

Note: Developers should use req.signal inside async operations to properly support request cancellation.

Circuit Breaker Plugin

Protects unstable endpoints from repeated failures.

export const config = {
    plugins: {
        get: {
            "circuit-breaker": {
                config: {
                    threshold: 5,
                    cooldown: 10000
                }
            }
        }
    }
};

Retry Plugin

Retries failed handlers automatically.

export const config = {
    plugins: {
        get: {
            retry: {
                config: {
                    retries: 3,
                    delay: 1000
                }
            }
        }
    }
};

Examples - TS

import { RouteConfig } from "file-routing-expressjs";

export const config: RouteConfig = {
    plugins: {
        get: {
            cache: true,

            timeout: {
                config: {
                    ms: 5000
                }
            }
        },

        post: {
            retry: {
                config: {
                    retries: 3
                }
            }
        }
    }
};

Note: Any route handlers that are not explicitly defined will use the all plugins if they exist.

CLI

The package ships with a built-in CLI that allows you to inspect and collect your application's endpoints without starting the server.

Once installed globally:

npm install -g file-routing-expressjs

you can use the fre command directly.

Collect Endpoints

Collect and visualize all mapped endpoints from your routes directory.

fre collect

Options

| Option | Type | Description | Default | | --------------- | ----------------------- | --------------------- | -------------- | | --target | string | Routes root directory | ./src/routes | | --output | tree \| table \| json | Output renderer | tree |

Tree Output (default)

fre collect --target ./src/routes

Example output:

/
  [GET] /
    ├─ middlewares: authMiddleware
    ├─ plugins: cache, timeout

  [POST] /
    ├─ plugins: retry

Table Output

fre collect \
  --target ./src/routes \
  --output table

JSON Output

fre collect \
  --target ./src/routes \
  --output json

Warnings

The CLI does not stop on partial failures.

Unknown plugins, invalid files or route loading errors will be displayed as warnings while still returning the successfully collected endpoints.

[WARN] Unknown plugin "cache" in route "/"

This allows developers to debug route issues incrementally without blocking the collection process.