Utility System

/**
 * The stack that is used to store the elements.
 * Generally, you don't need to use this class directly.
 * 
 * When using the stack, users can call stack.open to push a new element into the stack.
 * And use stack.push to push a node into the top element.
 * Then use stack.close to close the top element and pop it.
 * 
 * For example: stack.open(A).push(B).push(C).close() will generate a structure like A(B, C).
 */
class Stack<Node, Element extends StackElement<Node>> {
  protected elements: Element[];
  
  /**
   * Get the size of the stack.
   * @returns Number of elements in the stack
   */
  size(): number;
  
  /**
   * Get the top element of the stack.
   * @returns Top element or undefined if stack is empty
   */
  top(): Element | undefined;
  
  /**
   * Push a node into the top element.
   * @param node - Node to push into top element
   */
  push(node: Node): void;
  
  /**
   * Push a new element.
   * @param node - Element to push onto stack
   */
  open(node: Element): void;
  
  /**
   * Close the top element and pop it.
   * @returns The popped element
   * @throws Error if stack is empty
   */
  close(): Element;
}

/**
 * The element of the stack, which holds an array of nodes.
 */
abstract class StackElement<Node> {
  /**
   * A method that can push a node into the element.
   * @param node - Node to push
   * @param rest - Additional nodes to push
   */
  abstract push(node: Node, ...rest: Node[]): void;
}

import { Stack, StackElement } from "@milkdown/transformer";

// Custom stack element implementation
class MyStackElement extends StackElement<string> {
  private items: string[] = [];
  
  push(node: string, ...rest: string[]): void {
    this.items.push(node, ...rest);
  }
  
  getItems(): string[] {
    return this.items;
  }
}

// Using the stack
const stack = new Stack<string, MyStackElement>();
const element = new MyStackElement();

stack.open(element);
stack.push("item1");
stack.push("item2");
const closedElement = stack.close();

console.log(closedElement.getItems()); // ["item1", "item2"]

/**
 * The universal type of a node in mdast.
 */
type MarkdownNode = Node & {
  children?: MarkdownNode[];
  [x: string]: unknown;
};

/**
 * JSON value type for representing arbitrary JSON data.
 */
type JSONValue = 
  | string 
  | number 
  | boolean 
  | null 
  | JSONValue[] 
  | { [key: string]: JSONValue };

/**
 * JSON record type for object properties.
 */
type JSONRecord = Record<string, JSONValue>;

/**
 * The type of remark instance.
 */
type RemarkParser = ReturnType<typeof remark>;

/**
 * Node type for remark transformer parameters.
 */
type Node = Parameters<Transformer>[0];

/**
 * Root type for remark stringify parameters.
 */
type Root = Parameters<(typeof remark)['stringify']>[0];

/**
 * Raw plugin type for remark integration.
 */
type RemarkPluginRaw<T> = Plugin<[T], Root>;

/**
 * The universal type of a remark plugin.
 */
interface RemarkPlugin<T = Record<string, unknown>> {
  plugin: Plugin<[T], Root>;
  options: T;
}

import { RemarkPlugin, RemarkParser } from "@milkdown/transformer";
import { remark } from "remark";

// Define a custom plugin
const myPlugin: RemarkPlugin<{ prefix: string }> = {
  plugin: (options) => (tree, file) => {
    // Transform tree based on options
    if (options.prefix) {
      // Add prefix to all text nodes
    }
  },
  options: { prefix: ">> " }
};

// Use plugin with remark
const remarkInstance: RemarkParser = remark()
  .use(myPlugin.plugin, myPlugin.options);

// Plugin with type safety
const typedPlugin: RemarkPlugin<{
  enableFeature: boolean;
  maxDepth: number;
}> = {
  plugin: ({ enableFeature, maxDepth }) => (tree) => {
    if (enableFeature) {
      // Process tree with maxDepth limit
    }
  },
  options: {
    enableFeature: true,
    maxDepth: 5
  }
};

/**
 * Type guard to check if a node has text content.
 */
function hasText(node: Node): node is Node & { text: string };

/**
 * Type guard to check if an object is a ProseMirror Fragment.
 */
function isFragment(x: Node | Fragment): x is Fragment;

import { MarkdownNode, JSONRecord } from "@milkdown/transformer";

// Working with markdown nodes
function processMarkdownNode(node: MarkdownNode): void {
  console.log(`Processing ${node.type}`);
  
  if (node.children) {
    node.children.forEach(child => {
      processMarkdownNode(child);
    });
  }
  
  // Access arbitrary properties safely
  if (node.depth && typeof node.depth === 'number') {
    console.log(`Heading depth: ${node.depth}`);
  }
}

// Working with JSON records
function createNodeProps(data: any): JSONRecord {
  const props: JSONRecord = {};
  
  if (typeof data.id === 'string') props.id = data.id;
  if (typeof data.level === 'number') props.level = data.level;
  if (Array.isArray(data.classes)) props.classes = data.classes;
  
  return props;
}

// Type-safe node creation
interface CustomMarkdownNode extends MarkdownNode {
  type: 'custom';
  customProp: string;
}

function isCustomNode(node: MarkdownNode): node is CustomMarkdownNode {
  return node.type === 'custom' && typeof node.customProp === 'string';
}

// Error types that may be thrown during transformation
interface TransformationError extends Error {
  name: 'TransformationError';
  node?: MarkdownNode | Node;
  context?: string;
}

interface ParserMatchError extends Error {
  name: 'ParserMatchError';
  node: MarkdownNode;
}

interface SerializerMatchError extends Error {
  name: 'SerializerMatchError'; 
  nodeType: NodeType | MarkType;
}

import { ParserState } from "@milkdown/transformer";

try {
  const parser = ParserState.create(schema, remark());
  const doc = parser(markdownText);
} catch (error) {
  if (error.name === 'ParserMatchError') {
    console.error(`No parser found for node type: ${error.node.type}`);
  } else if (error.name === 'SerializerMatchError') {
    console.error(`No serializer found for node type: ${error.nodeType.name}`);
  } else {
    console.error('Unexpected transformation error:', error);
  }
}