mongoose-find-or-error

Simple Mongoose plugin for rejecting findOne and findById promises which resolve null.

Installation

npm install mongoose-find-or-error

Why create this plugin?

I find myself many times wanting to end a promise chain if a document is not found in the database. Without this plugin or similar solution I would end up doing something similar to this:

User.findById(userId)
  .then(user => {
    if(!user) {
      return Promise.reject('User was not found');
    }
 
    return doSomethingWithUser(user)
  })
  .then(someData => {
    // ...
  });
  .catch(err => {
    // ...
  });

Why not reduce the boilerplate by doing something like this:

User.findByIdOrError(userId)
  .then(user => doSomethingWithUser(user))
  .then(someData => {
    // ...
  });
  .catch(err => {
    // ...
  });

How to use

Hook the plugin to a schema:

// example.js
 
const mongoose = require('mongoose');
const findOrErrorPlugin = require('mongoose-find-or-error');
 
const schema = new mongoose.Schema({
  name: String
});
 
schema.plugin(findOrErrorPlugin);
 
mongoose.model('Example', schema);

Execute a query:

const Example = require('./example');
 
// use with findById
 
Example.findByIdOrError('idNotInDatabase')
  .then(() => {
    console.log('Only executed when document is found');
  })
  .catch(err => {
    console.log(err);
  });
 
 // or use with findOne
 
 Example.findOneOrError({ name: 'plugin example' })
   .then(() => {
     console.log('Only executed when document is found');
   })
   .catch(err => {
     console.log(err);
   });

You can override the default errors by defining plugin options:

schema.plugin(findOrErrorPlugin, {
  getFindByIdError: (id, modelName) => new MyCustomError(`Couldn't find ${modelName} by id ${id}`),
  getFindOneError: (query, modelName) => new MyCustomError(`Couldn't find ${modelName} by query`)
});

Running tests

npm test