Detect circular references in objects

circular.js

export const isCircular = target => {
  const map = new WeakMap()
  const detect = obj => {
    if (obj === null || typeof obj !== 'object') return false
    if (map.get(obj)) return true
    map.set(obj, true)
    return Object.values(obj).some(objProp => detect(objProp))
  }
  return detect(target)
}