objectFetch // Extending JavaScript with ease (beginner level tutorial)

objectFetch.js

const objectFetch = (object, propertyName) => {
  if (object.hasOwnProperty(propertyName)) {
    return object[propertyName]
  }
  
  throw new ReferenceError(`key not found: ${propertyName}`)
}

const collectorGroup = { target_count: 10 }

objectFetch(collectorGroup, 'target_count') // returns 10
objectFetch(collectorGroup, 'targets_count') // throws ReferenceError