mock-repo


A Node.js generic mock repo for simulating repositories in the
[Repository Pattern][1]. Helps to avoid touching the database when testing
business logic

Installation

``bash
$ npm install --save-dev mock-repo
`

Overview

This module exports an ES6 Class with simple methods that are most commonly
present in Repositories. You can extend if you need more methods.

Usage

A Class can be persisted if it satisfies the following criteria:

- 1st argument of it's constructor accepts an Object that contains
at least all the persistable properties.
- It has a props property that contains all the props that should be
persisted.

`javascript
class User {
constructor({ id_user = Guid.raw(), name }) {
this.props = {
id_user,
name
}

// Anything outside props will not be persisted
// - e.g age property will not be persisted
this.age = 15
}

getName() {
return this.name
}
}
`

- upsert(db, instance)

If the provided object pre-exists by primaryKey, then the repo will update
the existing object, otherwise it will insert it.

- get(db, filter)

Returns an item by some specified criteria.

You can include multiple criteria,
but be aware that all criteria must match (it simulates an SQL andWhere()).

- getAll(db, filter)

Same as get() but returns multiple instances. If no filter is provided,
it returns all instances.

$3

In the following example we are going to:

- Insert a user with name 'John Doe' and id_user 1.
- Then update his name to 'John Doooe'.
- Then get him back by the id_user we used when we first inserted him.

The following example assumes your Class looks like this:

`javascript
class User {
constructor({ id_user = Guid.raw(), name }) {
this.props = {
id_user,
name
}
}
}
`

Then:

`javascript

const MockRepo = require('mock-repo')
const userRepo = new MockRepo({
primaryKey: 'id_user',
constructAs: data => new User(data)
})

/*
1st argument on all* methods is supposed to be the db object in
* production, when you actually use a real database.
*
* You can pass null when using this module
*/
userRepo.upsert(null, new User({ id_user: 1, name: 'John Doe' }))
.then(() => {
return userRepo.upsert(null, new User({ id_user: 1, name: 'John Doooe' }))
})
.then(() => {
return userRepo.get(null, { id_user: 1 })
})
.then(result => {
console.log(result) // logs User { id_user: 1, name: 'John Doooe' }
console.log(userRepo.items.length) // logs '1'
return
})
`

Note: Stored items are held in the items prop of the Mock Repo, i.e
userRepo.items, will return all the stored users.

Tests

`bash

$ npm test

``

Authors

- Nicholas Kyriakides, [@nicholaswmin][2]

[1]: https://martinfowler.com/eaaCatalog/repository.html
[2]: https://github.com/nicholaswmin