Utilities

/**
 * Check if value is a string
 * @param obj - Value to check
 * @returns True if value is a string
 */
function isString(obj: any): boolean;

import { utils } from "remarkable";

// Type checking in custom rules
function customRule(state, start, end, silent) {
  const line = state.getLines(start, start + 1, 0, false);
  
  if (!utils.isString(line)) {
    return false;
  }
  
  // Process string content
  return processLine(line);
}

// Validating plugin options
function myPlugin(md, options) {
  if (options.template && !utils.isString(options.template)) {
    throw new Error('Template option must be a string');
  }
}

/**
 * Check if object has own property
 * @param object - Object to check
 * @param key - Property key to look for
 * @returns True if object has the property
 */
function has(object: object, key: string): boolean;

/**
 * Merge multiple objects into target object (Object.assign polyfill)
 * @param target - Target object to merge into
 * @param sources - Source objects to merge from
 * @returns Modified target object
 */
function assign(target: object, ...sources: object[]): object;

import { utils } from "remarkable";

// Property checking in custom rules
function processToken(token, options) {
  if (utils.has(token, 'attrs') && token.attrs) {
    // Process attributes
    token.attrs.forEach(([name, value]) => {
      console.log(`${name}: ${value}`);
    });
  }
  
  if (utils.has(options, 'customClass')) {
    token.attrSet('class', options.customClass);
  }
}

// Object merging for plugin options
function configurePlugin(defaultOptions, userOptions) {
  return utils.assign({}, defaultOptions, userOptions);
}

// Example usage
const defaultOpts = { theme: 'default', showNumbers: false };
const userOpts = { showNumbers: true, highlighter: 'prism' };
const finalOpts = utils.assign({}, defaultOpts, userOpts);
// Result: { theme: 'default', showNumbers: true, highlighter: 'prism' }

/**
 * Unescape markdown escape sequences
 * @param str - String with markdown escapes
 * @returns String with escapes resolved
 */
function unescapeMd(str: string): string;

/**
 * Replace HTML entities with their character equivalents
 * @param str - String containing HTML entities
 * @returns String with entities replaced
 */
function replaceEntities(str: string): string;

/**
 * Escape HTML special characters
 * @param str - String to escape
 * @returns HTML-safe string
 */
function escapeHtml(str: string): string;

import { utils } from "remarkable";

// Unescaping markdown in custom rules
function processMarkdown(content) {
  // Handle escaped characters like \* \_ \#
  const unescaped = utils.unescapeMd(content);
  return unescaped;
}

// Entity replacement in text processing
function processEntities(text) {
  // Convert & < > " ' etc. to actual characters
  const withEntities = utils.replaceEntities(text);
  return withEntities;
}

// HTML escaping for safe output
function customTextRule(tokens, idx, options, env, renderer) {
  const token = tokens[idx];
  const safeContent = utils.escapeHtml(token.content);
  return safeContent;
}

// Example transformations
console.log(utils.unescapeMd('\\*not italic\\*'));     // → *not italic*
console.log(utils.replaceEntities('&lt;p&gt;'));       // → <p>
console.log(utils.escapeHtml('<script>alert(1)</script>')); // → &lt;script&gt;alert(1)&lt;/script&gt;

/**
 * Check if Unicode code point is valid
 * @param code - Unicode code point to validate
 * @returns True if code point is valid
 */
function isValidEntityCode(code: number): boolean;

/**
 * Convert Unicode code point to string character
 * @param code - Unicode code point
 * @returns String character for the code point
 */
function fromCodePoint(code: number): string;

import { utils } from "remarkable";

// Unicode validation
const validCode = 0x1F600; // 😀 emoji
console.log(utils.isValidEntityCode(validCode)); // → true

const invalidCode = 0xD800; // Surrogate pair range
console.log(utils.isValidEntityCode(invalidCode)); // → false

// Code point conversion
console.log(utils.fromCodePoint(0x1F600)); // → 😀
console.log(utils.fromCodePoint(0x41));    // → A
console.log(utils.fromCodePoint(0x20AC));  // → €

// Custom entity processing
function processCustomEntities(text) {
  return text.replace(/&#(\d+);/g, (match, code) => {
    const codeNum = parseInt(code, 10);
    return utils.isValidEntityCode(codeNum) 
      ? utils.fromCodePoint(codeNum) 
      : match; // Keep original if invalid
  });
}

import { Remarkable, utils } from "remarkable";

const md = new Remarkable();

// Safe text rendering with escaping
md.renderer.rules.text = function(tokens, idx, options, env, renderer) {
  const token = tokens[idx];
  return utils.escapeHtml(token.content);
};

// Custom code block with entity handling
md.renderer.rules.code = function(tokens, idx, options, env, renderer) {
  const token = tokens[idx];
  const content = utils.replaceEntities(token.content);
  const escaped = utils.escapeHtml(content);
  
  if (token.block) {
    return `<pre><code>${escaped}</code></pre>\n`;
  }
  return `<code>${escaped}</code>`;
};

// Link processing with validation
md.renderer.rules.link_open = function(tokens, idx, options, env, renderer) {
  const token = tokens[idx];
  const href = token.attrGet('href');
  
  if (utils.isString(href)) {
    const safeHref = utils.escapeHtml(href);
    token.attrSet('href', safeHref);
  }
  
  return '<a' + renderer.renderAttrs(token) + '>';
};

function safeContentPlugin(md, options) {
  const defaultOptions = {
    escapeLevel: 'basic',
    preserveEntities: false
  };
  
  // Merge options safely
  const opts = utils.assign({}, defaultOptions, options);
  
  // Custom rule for safe content processing
  md.core.ruler.push('safe_content', function(state) {
    state.tokens.forEach(token => {
      if (token.type === 'inline' && token.children) {
        token.children.forEach(child => {
          if (child.type === 'text' && utils.isString(child.content)) {
            // Process text content safely
            if (!opts.preserveEntities) {
              child.content = utils.replaceEntities(child.content);
            }
            if (opts.escapeLevel === 'full') {
              child.content = utils.escapeHtml(child.content);
            }
          }
        });
      }
    });
  });
}

// Usage
const md = new Remarkable().use(safeContentPlugin, {
  escapeLevel: 'full',
  preserveEntities: true
});

function processTokens(tokens) {
  return tokens.map(token => {
    // Check for required properties
    if (!utils.has(token, 'type')) {
      throw new Error('Token missing required type property');
    }
    
    // Process text tokens
    if (token.type === 'text' && utils.isString(token.content)) {
      const processed = utils.assign({}, token);
      processed.content = utils.unescapeMd(token.content);
      return processed;
    }
    
    // Process container tokens
    if (utils.has(token, 'children') && Array.isArray(token.children)) {
      const processed = utils.assign({}, token);
      processed.children = processTokens(token.children);
      return processed;
    }
    
    return token;
  });
}

interface Utils {
  /** Type checking */
  isString(obj: any): boolean;
  
  /** Object utilities */
  has(object: object, key: string): boolean;
  assign(target: object, ...sources: object[]): object;
  
  /** String processing */
  unescapeMd(str: string): string;
  replaceEntities(str: string): string;
  escapeHtml(str: string): string;
  
  /** Entity processing (advanced utilities) */
  isValidEntityCode(code: number): boolean;
  fromCodePoint(code: number): string;
}

// Import patterns
import { utils } from "remarkable";
const { utils } = require("remarkable");

// Individual function imports (not available - import from utils object)
// import { escapeHtml } from "remarkable"; // ❌ Not available
// const { escapeHtml } = utils; // ✅ Correct way