@stejnar/mongoopose

Table of contents

• Introduction
• Prerequisites
• Installation
• Usage
• Documentation

Introduction

Mongoopose is very simple and currently provides by far not all of the mongoose api. It wraps mongoose and behaves like an adapter, based on functional programming patterns and Promises to escape the pyramid of doom.

Combining function composition and Promises comes in very handy, when complex database queries make your head hurt. Your code becomes more readable and easier to reason about, because you will start to see how your data flows.

Mongoopose itself has only a few very basic wrapper functions like find, findOne, save and remove, but leaves you with a simple possibility to compose every async task into the pipeline.

Prerequisites

Most likely you would have a basic understanding of functional programming, but happily you do not need it to just use it, because the implementation is very straight forward.

There is no npm dependency as you can see in package.json, because mongoopose uses dependency injection.
In a nutshell... it depends on mongoose, which means you also have a MongoDB setup.

Installation

npm install @stejnar/mongoopose

Usage

Enough talking. Here is some code:

    const mongoopose = require('mongoopose')
    const mongoose = require('mongoose')
    
    // initialize mongoose model
    const userSchema = require('./schema')
    const UserModel = mongoose.model('User', userSchema)
    
    // initialize mongoopose model
    const {compose, Params} = mongoopose
    const User = mongoopose.model(UserModel)
    
    // design the queries
    const selectJon = params => Params({select: {email: '[e-mail]'}})
    const updateJon = params => Params({query: {$set: {lifes: 2}}})
    
    // composition reads from left to right
    const pipeline = compose(
        User.findOne(selectJon),
        User.update(updateJon)
    )
    pipeline(Params()) // empty initial params
        .then(params => console.log(params)) // params.user => jon 
        .catch(error => console.error(error))

See functors.test.js for more examples

Documentation

• mongoopose
• Model
• Params

mongoopose

mongoopose.model()

Parameters:
A model that gets returned from mongoose.model()

Returns:
Model

mongoopose.compose()

Parameter:
...function, you should only pass findById(), findOne(), find(), save(), update(), remove() and/or pipe()

Returns:
function(Params), that returns a Promise

mongoopose.Params

Model

• Model.findById()
• Model.findOne()
• Model.find()
• Model.save()
• Model.update()
• Model.remove()

Note: All methods, but pipe(), take the same input and give the same output. As follows:

Parameter:
function(query = Params => Params), optional and defaults into no Params transformation

Returns:
function(Params), that returns a Promise

Model.pipe()

Parameter:
function(action), action can be any function that gets resolve, reject and params passed into and calls resolve or reject

Returns:
function(Params), that returns a Promise

Params

Params.as

Type: String
Default: mongoose.Model.modelName
This is the key with that a queries result gets assigned to Params.

Params.select

Type: Object
This is the selector that gets passed into mongoose queries.

Params.query

Type: Object
This is the update object for Model.update()

Params.save

Type: Object
This gets passed into the mongoose model constructor for Model.save().

Params.add()

Parameters:

• result any,
  
• name String, this is the key with that result gets assigned to Params

Returns:
Params

Params.assign()

Parameters:
obj, any

Returns:
Params

Params.toError()

Parameters:

• result any,
  
• name String

Returns:
Error