Guide to accessing Realm(JavaScript) object in an asynchronous manner and integrating it with various services

Question

Guide to accessing Realm(JavaScript) object in an asynchronous manner and integrating it with various services

I have incorporated the following code into my project to open Realm asynchronously and integrate it with services.

RmProfile.js:

import Realm from 'realm';
const PrflSchema = {
  name: 'Profile',
  primaryKey: 'id',
  properties: {
    id            : {type: 'int'},
    mob            : {type: 'int'},
    name        : {type: 'string'},
  }
};

let RmPrfl;

Realm.open({
      schema: [PrflSchema],
      schemaVersion: 0
    }).then(realm => {
        RmPrfl = realm;
    })
    .catch(error => {
        console.log('Error in Opening PrflSchema');
        console.log(error);
      });

let ProfileServices= {
    getName: function(id) {
        let PrflInfo=RmPrfl.objectForPrimaryKey('Profile', id);
        if(PrflInfo){
            return PrflInfo.name;
        }
        else{
            return false;
        }
    }
}
module.exports = ProfileServices;

To utilize the realm services in other files, I am exporting them as follows

Profile.js:

import PrflSrvcs from './ProfileServices'
console.log(PrflSrvcs.getName('1253'));

The services are being exported, but an error is occurring stating that RmPrfl is undefined. This issue arises because Realm.Open() is executed asynchronously, and before its completion, the ProfileServices is executed.

As a beginner in Realm, could someone provide guidance on how to perform asynchronous transactions using Realm JavaScript?

An example would greatly aid in comprehension.

Thank you.

javascript realm

Answer 1

Answer №1

Have you considered wrapping the entire operation in a promise? For example:

let ProfileServices = () => {
    getName: function(id) {
      return new Promise((resolve, reject) => {
        Realm.open({
              schema: [PrflSchema],
              schemaVersion: 0
          })
          .then(realm => {
              let PrflInfo = realm.objectForPrimaryKey('Profile', id);
              resolve(PrflInfo || false)
          })
          .catch(error => {
              console.log('Error in Opening PrflSchema');
              console.log(error);
              reject(error)
          });
      })
    }
}

module.exports = ProfileServices

import PrflSrvcs from './ProfileServices'
PrflSrvcs.getName('1253')
  .then(name => { console.log(name) });

It might be more efficient to cache the realm and check if it's already open before running the query.

Answer 2

Have you considered wrapping the entire operation in a promise? For example:

let ProfileServices = () => {
    getName: function(id) {
      return new Promise((resolve, reject) => {
        Realm.open({
              schema: [PrflSchema],
              schemaVersion: 0
          })
          .then(realm => {
              let PrflInfo = realm.objectForPrimaryKey('Profile', id);
              resolve(PrflInfo || false)
          })
          .catch(error => {
              console.log('Error in Opening PrflSchema');
              console.log(error);
              reject(error)
          });
      })
    }
}

module.exports = ProfileServices

import PrflSrvcs from './ProfileServices'
PrflSrvcs.getName('1253')
  .then(name => { console.log(name) });

It might be more efficient to cache the realm and check if it's already open before running the query.

Answer 3

Answer №2

Although the documentation may not explicitly state it, it appears that Realm.open(config) actually caches the promised realm itself. This means you can utilize this API for all queries without any issues.

# Initial Ream.open():  took 176.50000000139698 milliseconds.
# Manually Cached:      took 0.5999999993946403 milliseconds.
# Second Realm.open():  took 0.19999999494757503 milliseconds.

Therefore, creating a manual cache only results in a slight increase in overhead without streamlining the API for realm access.

Below is the caching function implementation that was employed:

    private realm(): Promise<Realm> {
      return new Promise((resolve, reject) => {
        if (this.cachedRealm) {
          resolve(this.cachedRealm)
        } else {
          Realm.open(this.config)
            .then(realm => {
              this.cachedRealm = realm
              resolve(realm)
            })
            .catch(error => {
                console.error(error);
                reject(error)
            });
        }
      })
    }

Answer 4

Although the documentation may not explicitly state it, it appears that Realm.open(config) actually caches the promised realm itself. This means you can utilize this API for all queries without any issues.

# Initial Ream.open():  took 176.50000000139698 milliseconds.
# Manually Cached:      took 0.5999999993946403 milliseconds.
# Second Realm.open():  took 0.19999999494757503 milliseconds.

Therefore, creating a manual cache only results in a slight increase in overhead without streamlining the API for realm access.

Below is the caching function implementation that was employed:

    private realm(): Promise<Realm> {
      return new Promise((resolve, reject) => {
        if (this.cachedRealm) {
          resolve(this.cachedRealm)
        } else {
          Realm.open(this.config)
            .then(realm => {
              this.cachedRealm = realm
              resolve(realm)
            })
            .catch(error => {
                console.error(error);
                reject(error)
            });
        }
      })
    }

Guide to accessing Realm(JavaScript) object in an asynchronous manner and integrating it with various services

RmProfile.js:

Profile.js:

Answer №1

Answer №2

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