Proof-Of-Concept that overrides the global require() function in MarkLogic to (eventually) operate like Node

require-override.sjs

// IIFE to avoid polluting global scope.
(function() {
  /** {@link https://nodejs.org/api/modules.html#modules_all_together}
  /*
  require(X) from module at path Y
  1. If X is a core module,
     a. return the core module
     b. STOP
  2. If X begins with './' or '/' or '../'
     a. LOAD_AS_FILE(Y + X)
     b. LOAD_AS_DIRECTORY(Y + X)
  3. LOAD_NODE_MODULES(X, dirname(Y))
  4. THROW "not found"

  LOAD_AS_FILE(X)
  1. If X is a file, load X as JavaScript text.  STOP
  2. If X.js is a file, load X.js as JavaScript text.  STOP
  3. If X.json is a file, parse X.json to a JavaScript Object.  STOP
  4. If X.node is a file, load X.node as binary addon.  STOP

  LOAD_AS_DIRECTORY(X)
  1. If X/package.json is a file,
     a. Parse X/package.json, and look for "main" field.
     b. let M = X + (json main field)
     c. LOAD_AS_FILE(M)
  2. If X/index.js is a file, load X/index.js as JavaScript text.  STOP
  3. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP
  4. If X/index.node is a file, load X/index.node as binary addon.  STOP

  LOAD_NODE_MODULES(X, START)
  1. let DIRS=NODE_MODULES_PATHS(START)
  2. for each DIR in DIRS:
     a. LOAD_AS_FILE(DIR/X)
     b. LOAD_AS_DIRECTORY(DIR/X)

  NODE_MODULES_PATHS(START)
  1. let PARTS = path split(START)
  2. let I = count of PARTS - 1
  3. let DIRS = []
  4. while I >= 0,
     a. if PARTS[I] = "node_modules" CONTINUE
     b. DIR = path join(PARTS[0 .. I] + "node_modules")
     c. DIRS = DIRS + DIR
     d. let I = I - 1
  5. return DIRS
  */
  
  const _require = require;
  /**
   * Overrides the default `require()` global to implement
   * custom path resolution logic.
   *
   * @param {string} path - The path to load
   * @returns {*} - `module.exports` from the included module
   * @throws {Error} - Rethrows underlying {@link Error} if `path` can’t be resolved
   */
  require = function(path) {
    const steps = path.split(/[\/\\]/);
    if(isRelative(path)) { return _require(path); }
    try {
      return _require('' + path);
    } catch(error) {
      if('XDMP-MODNOTFOUND' === error.name) {
        return _require(path + '/index.js')
      }
      throw error;
    }
  };
  function isRelative(path) {
    return /^\.{1,2}?[\\\/]/.test(path);
  }
  function resolve(path) { };
  /** {@link https://nodejs.org/api/globals.html#globals_require_resolve} */
  require.resolve = resolve;
})();