import { get } from "lodash";
import { Node, Render, RenderableNode } from "..";

/**
 * Checks if a node is of one of the specified types. If it is, it returns true and narrows the
 * type of the node.
 */
export function isOfType<
  T extends Node["type"],
  P extends Node | RenderableNode
>(node: P, types: T[]): node is Extract<P, { type: T }> {
  return types.includes(node.type as T);
}

/**
 * Checks if a node has the specified property. If it does, it returns true and narrows the type
 * of the node to types that has the property.
 */
export function hasProperty<
  K extends string,
  T extends Node | Render<Node> | RenderableNode
>(obj: T, prop: K): obj is Extract<T, { [P in K]?: any }> {
  return typeof get(obj, prop) !== "undefined";
}