Function toRef

packages/reactivity/src/ref.ts:503–517

(
  source: Record<PropertyKey, any> | MaybeRef,
  key?: string | number | symbol,
  defaultValue?: unknown,
)

): ToRef<Exclude<ToRefValue<T, K>, undefined>>
/*@__NO_SIDE_EFFECTS__*/
export function toRef(
  source: Record<PropertyKey, any> | MaybeRef,
  key?: string | number | symbol,
  defaultValue?: unknown,
): Ref {
  if (isRef(source)) {
    return source
  } else if (isFunction(source)) {
    return new GetterRefImpl(source) as any
  } else if (isObject(source) && arguments.length > 1) {
    return propertyToRef(source, key!, defaultValue)
  } else {
    return ref(source)
  }
}

function propertyToRef(
  source: Record<PropertyKey, any>,