LevelSandbox.js
// Add data to levelDB with key and value (Promise)
Add data to levelDB with key and value (Promise)
Add data to levelDB with key and value ( Promise )
async addLevelDBData(key, value) {
    let self = this;
    return new Promise((resolve, reject) => {
      self.db.put(key, value, (err) => {
        if (err) reject(err);
        resolve(value);
      })
    });
  }
async addLevelDBData ( key , value ) { let self = this ; return new Promise ( ( resolve , reject ) => { self . db . put ( key , value , ( err ) => { if ( err ) reject ( err ) ; resolve ( value ) ; } ) } ) ; }
Add data to levelDB with key and value (Promise)
Add data to levelDB with key and value ( Promise )