API mock with local_storage

local_storage.js

import _ from 'lodash'

export const get = (path, data) => {
  const collection = JSON.parse(localStorage.getItem(path)) || []
  if (data && data.id) {
    return Promise.resolve(_.find(collection, ['id', data.id]))
  }
  return Promise.resolve(collection)
}

export const add = (path, data) => {
  const collection = JSON.parse(localStorage.getItem(path)) || []
  const item = Object.assign({}, data, { id: collection.length + 1 })
  localStorage.setItem(path, JSON.stringify([...collection, item]))
  return Promise.resolve(item)
}

export const save = (path, data) => {
  const collection = JSON.parse(localStorage.getItem(path)) || []
  const index = _.findIndex(collection, ['id', data.id])
  const item = Object.assign({}, collection[index], data)
  localStorage.setItem(path, JSON.stringify([
    ...collection.slice(0, index),
    item,
    ...collection.slice(index + 1),
  ]))
  return Promise.resolve(item)
}

export const update = (path, data) => save(path, data)

export const remove = (path, { id }) => {
  const collection = JSON.parse(localStorage.getItem(path)) || []
  const index = _.findIndex(collection, ['id', id])
  const item = collection[index]
  localStorage.setItem(path, JSON.stringify([
    ...collection.slice(0, index),
    ...collection.slice(index + 1),
  ]))
  return Promise.resolve(item)
}

local_storage_tests.js

import 'mock-local-storage'
import test from 'ava'

import { add, get, save } from '../src/local_storage'

test.beforeEach(() => localStorage.clear())

test.serial('get all', t => {
  t.plan(1)
  const data = [{ title: 'wat' }]
  localStorage.setItem('/coffees', JSON.stringify(data))
  return get('/coffees')
    .then(response => t.same(response, data))
})

test.serial('get single', t => {
  t.plan(1)
  const item = { title: 'a title', id: 2 }
  const data = [{ title: 'wat', id: 42 }, item]
  localStorage.setItem('/coffees', JSON.stringify(data))
  return get('/coffees', { id: 2 })
    .then(response => t.same(response, item))
})

test.serial('add', t => {
  t.plan(2)
  const data = [{ title: 'wat', id: 42 }]
  localStorage.setItem('/coffees', JSON.stringify(data))
  return add('/coffees', { title: 'a title' })
    .then(response => {
      t.same(response, { title: 'a title', id: 2 })
      t.same(JSON.parse(localStorage.getItem('/coffees')), [...data, { title: 'a title', id: 2 }])
    })
})

test.serial('save', t => {
  t.plan(2)
  const data = [{ title: 'wat', id: 42 }, { title: 'wat', id: 5 }]
  localStorage.setItem('/coffees', JSON.stringify(data))
  return save('/coffees', { title: 'a title', id: 5 })
    .then(response => {
      t.same(response, { title: 'a title', id: 5 })
      t.same(JSON.parse(localStorage.getItem('/coffees')), [data[0], { title: 'a title', id: 5 }])
    })
})