ExceptionLibrary Documentation

NPM Library to handle different kind of api exceptions in a Express app

Installation

---

Install library using npm package manager

npm install exception-library

Usage

---

Add ExceptionHandler middleware to your express application

import express from "express";
import { ExceptionHandler } from "exception-library";

const app = express();

// After adding your route handlers

app.use(ExceptionHandler);

After this throw different types errors as your needs inside a route

Supported Exceptions

---

Bad Gateway Exception

router.get('/path', (req, res) => {
    ...

    throw new BadGatewayError("some reason")

    ...
})

Bad Request Exception

router.get('/path', (req, res) => {
    ...

    throw new BadRequestError("some reason")

    ...
})

Forbiddon Exception

router.get('/path', (req, res) => {
    ...

    throw new ForbiddenError("some reason")

    ...
})

Internal Server Exception

router.get('/path', (req, res) => {
    ...

    throw new InternalServerError("some reason")

    ...
})

Method not allowed Exception

router.get('/path', (req, res) => {
    ...

    throw new MethodNotAllowedError("some reason")

    ...
})

Not found Exception

router.get('/path', (req, res) => {
    ...

    throw new NotFoundError("some reason")

    ...
})

Not Implemented Exception

router.get('/path', (req, res) => {
    ...

    throw new NotImplementedError("some reason")

    ...
})

Request Time Out Exception

router.get('/path', (req, res) => {
    ...

    throw new RequestTimeOutError("some reason")

    ...
})

Unauthorized Exception

router.get('/path', (req, res) => {
    ...

    throw new UnorthorizedError("some reason")

    ...
})

Data Validation Exception with Joi

router.get('/path', (req, res) => {
    ...
    // Only support with Joi validation
    const errors = [{
        message: detail.message,
        field: detail.context.label,
        errorType: detail.type
    }]

    throw new DataValidationError(errors)

    ...
})

Data Types

---

Return Error Type

Exceptions returns from API like follwoing format

interface ReturnErrorType<Type> {
    statusCode: number
    errors: Type[]
    type: string
}

Validation Error Type

Data should be in this type to pass to the DataValidationError

interface ValidationErrorType {
  message: string;
  field: string | undefined;
  errorType: string;
}