naive-ui/packages/utils/installThemeableComponent.js

function getTheme(component) {
  let cursor = component
  while (cursor.$parent) {
    const name = cursor.$options.name
    if (cursor.synthesizedTheme) {
      return cursor.synthesizedTheme
    }
    if (name === 'NApp') {
      return cursor.theme || null
    }
    cursor = cursor.$parent
  }
  return null
}

function install(Vue, Component, name) {
  const prototypeProxy = new Proxy(
    function() {
      return Component
    },
    {
      apply(target, thisArg, argumentsList) {
        if (thisArg instanceof Vue) {
          Component.theme = getTheme(thisArg)
          console.log('theme', getTheme(thisArg))
        }
        return target.bind(thisArg)(...argumentsList)
      }
    }
  )
  Object.defineProperty(Vue.prototype, name, {
    get: prototypeProxy
  })
}

export { getTheme, install }