rofrischmann/fela

import { arrayEach } from 'fast-loops'

const basicStatics = {
  name: true,
  length: true,
  prototype: true,
  caller: true,
  callee: true,
  arguments: true,
  arity: true,
}

const mergableStatics = ['contextTypes', 'defaultProps']
const blockedStatics = {
  childContextTypes: true,
  propTypes: true,
  getDerivedStateFromProps: true,
  contextType: true,
}

export default function hoistStatics(target, source) {
  if (typeof source === 'string') {
    return target
  }

  const statics = Object.getOwnPropertyNames(source).filter(
    (property) => !basicStatics[property]
  )

  arrayEach(statics, (property) => {
    if (!target.hasOwnProperty(property) && !blockedStatics[property]) {
      try {
        // Avoid failures from read-only properties
        const descriptor = Object.getOwnPropertyDescriptor(source, property)

        if (descriptor) {
          Object.defineProperty(target, property, descriptor)
        }
      } catch (e) {
        // TODO: warning
      }
    }
  })

  arrayEach(mergableStatics, (property) => {
    if (source[property]) {
      const targetStatics = target[property] || {}

      target[property] = {
        ...source[property],
        ...targetStatics,
      }
    }
  })

  return target
}