index.thread.js

import { self } from 'react-native-threads'
// realmP = Realm.open(options)
import { realmP } from './src/realm/schema'

// listen for messages
self.onmessage = (message) => {
  const data = JSON.parse(message)
  const { id, operation } = data
  switch (operation) {
    case 'query':
      realmP
      .then(query(data))
      .then((result) => ({ status: true, operation, id, result }))
      .then(JSON.stringify)
      .then(self.postMessage)
    break
    case 'load':
      realmP
      .then(load(data))
      .then((result) => ({ status: true, operation, id, result }))
      .then(JSON.stringify)
      .then(self.postMessage)
    break
    default:
      self.postMessage({ status: false, error: 'Operation not implemented' })
  }
}

export const query = ({ collection, method, args, slice }) => (realm) => {
  let result = null
  try {
    result = realm.objects(collection)[method](args)
    if (slice) {
      result = result.slice(slice[0], slice[1])
    }
    return result
  } catch (error) {
    return { success: false, error: error.message }
  }
}

export const load = ({ collection, slice }) => (realm) => {
  let result = null
  try {
    result = realm.objects(collection)
    if (slice) {
      result = result.slice(slice[0], slice[1])
    }
    return result
  } catch (error) {
    return { success: false, error: error.message }
  }
}

interface.js

import { Thread } from 'react-native-threads'
import uuid from 'uuid/v1'

const thread = new Thread('./index.thread.js')

const post = post = (payload) => {
  const message = JSON.stringify(payload)
  thread.postMessage(message)  
}

const requests = {

}

thread.onmessage = (message) => {
  const data = JSON.parse(message)
  const { status, id, result } = data
  const prop = requests[id]
  const { resolve, reject } = prop
  delete requests[id]

  if (status === true) return resolve(result)
  return reject(result)
}

export const query = (collection, method, args, opts) => {
  const id = uuid()
  return new Promise((resolve, reject) => {
    requests[id] = { resolve, reject }
    post({ operation: 'query', collection, method, args, id, ...opts })
  })
}

export const load = (collection, opts) => {
  const id = uuid()
  return new Promise((resolve, reject) => {
    requests[id] = { resolve, reject }
    post({ operation: 'load', collection, id, ...opts })
  })
}