http-errors-promise

Server side error handling service, best suited for promise chains, uses http-errors.

Basic Usage

  const error = require('http-errors-promise');
  
  router.get('/', function(req, res, next) {
    getStuffFromDB()
      .then(//...)
      .catch(function (error) {
        return error.respond(
          res,
          error, // error from the call 'getStuffFromDB'
          'Something went wrong' // error from this context
        );
      });
  });

Shining Use-case

function doSomething() {
  // returns a promise
  return new Promise((resolve, reject) => {
    // doing some stuff...
    if (someCondition) {
      resolve(result);
    } else {
      return error(null, 'messed up while doing something', 500);
    }
  })
}

function doSomethingElse() {
  // calls 'doSomething', does its own processing and returns a promise
  return doSomething()
    .then(result => {
      // does some stuff
      return newResult;
    })
    .catch(err => error(
      err,
      'Messed up while doing somethingElse'
    ));
}

function mainFunction() {
  doSomethingElse()
    .catch(err => {
      // here 'err' could either be from 'doSomething' or
      // 'doSomethingElse' based on what went wrong and where
      // the error actually originated from, more technically the
      // error properly bubbles up
    })
}

Methods

error(err, secErr, status = 500, dontReject)

• err error object recieved from a function call
• secErr error from the current context
• status http status, defaults to 500
• returns a rejected promise with the resulting error
• dontReject returns the resulting error instead of a rejected promise

error.respond(res, err, secErr, status = 500)

• similar to error method, except that it takes the express' response object and sends the response with the error instead of returning

error.make(err, status = 500)

• creates and returns an error using http-errors

makeCommonErrors(modelName)

• creates and returns commonly seen errors by using a dynamically set modelName in the error message, also using http-errors
• the common errors are defined in common.js (you're welcome to add new errors there)

Design inspired by ralusek's work on error handling