Find property by key in nested object

custom;js

function findByKey(obj, keyToFind) {
  return Object.entries(obj)
    .reduce((acc, [key, value]) => (key === keyToFind)
      ? acc.concat(value)
      : (typeof value === 'object')
      ? acc.concat(findByKey(value, keyToFind))
      : acc
    , [])
}

// Usage.
findByKey(obj, key)