src/shell.js

try {
  this['Module'] = Module;
  Module.test;
} catch(e) {
  this['Module'] = Module = {};
}

// The environment setup code below is customized to use Module.
// *** Environment setup code ***
var ENVIRONMENT_IS_NODE = typeof process === 'object' && typeof require === 'function';
var ENVIRONMENT_IS_WEB = typeof window === 'object';
var ENVIRONMENT_IS_WORKER = typeof importScripts === 'function';
var ENVIRONMENT_IS_SHELL = !ENVIRONMENT_IS_WEB && !ENVIRONMENT_IS_NODE && !ENVIRONMENT_IS_WORKER;

if (ENVIRONMENT_IS_NODE) {
  // Expose functionality in the same simple way that the shells work
  // Note that we pollute the global namespace here, otherwise we break in node
  Module['print'] = function(x) {
    process['stdout'].write(x + '\n');
  };
  Module['printErr'] = function(x) {
    process['stderr'].write(x + '\n');
  };

  var nodeFS = require('fs');
  var nodePath = require('path');

  Module['read'] = function(filename, binary) {
    filename = nodePath['normalize'](filename);
    var ret = nodeFS['readFileSync'](filename);
    // The path is absolute if the normalized version is the same as the resolved.
    if (!ret && filename != nodePath['resolve'](filename)) {
      filename = path.join(__dirname, '..', 'src', filename);
      ret = nodeFS['readFileSync'](filename);
    }
    if (ret && !binary) ret = ret.toString();
    return ret;
  };

  Module['readBinary'] = function(filename) { return Module['read'](filename, true) };

  Module['load'] = function(f) {
    globalEval(read(f));
  };

  if (!Module['arguments']) {
    Module['arguments'] = process['argv'].slice(2);
  }

  module.exports = Module;
}

if (ENVIRONMENT_IS_SHELL) {
  Module['print'] = print;
  if (typeof printErr != 'undefined') Module['printErr'] = printErr; // not present in v8 or older sm

  Module['read'] = read;
  Module['readBinary'] = function(f) {
    return read(f, 'binary');
  };

  if (!Module['arguments']) {
    if (typeof scriptArgs != 'undefined') {
      Module['arguments'] = scriptArgs;
    } else if (typeof arguments != 'undefined') {
      Module['arguments'] = arguments;
    }
  }
  
  this['{{{ EXPORT_NAME }}}'] = Module;
}

if (ENVIRONMENT_IS_WEB && !ENVIRONMENT_IS_WORKER) {
  if (!Module['print']) {
    Module['print'] = function(x) {
      console.log(x);
    };
  }

  if (!Module['printErr']) {
    Module['printErr'] = function(x) {
      console.log(x);
    };
  }

  this['{{{ EXPORT_NAME }}}'] = Module;
}

if (ENVIRONMENT_IS_WEB || ENVIRONMENT_IS_WORKER) {
  Module['read'] = function(url) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', url, false);
    xhr.send(null);
    return xhr.responseText;
  };

  if (!Module['arguments']) {
    if (typeof arguments != 'undefined') {
      Module['arguments'] = arguments;
    }
  }
}

if (ENVIRONMENT_IS_WORKER) {
  // We can do very little here...
  var TRY_USE_DUMP = false;
  if (!Module['print']) {
    Module['print'] = (TRY_USE_DUMP && (typeof(dump) !== "undefined") ? (function(x) {
      dump(x);
    }) : (function(x) {
      // self.postMessage(x); // enable this if you want stdout to be sent as messages
    }));
  }

  Module['load'] = importScripts;
}

if (!ENVIRONMENT_IS_WORKER && !ENVIRONMENT_IS_WEB && !ENVIRONMENT_IS_NODE && !ENVIRONMENT_IS_SHELL) {
  // Unreachable because SHELL is dependant on the others
  throw 'Unknown runtime environment. Where are we?';
}

function globalEval(x) {
  eval.call(null, x);
}
if (!Module['load'] == 'undefined' && Module['read']) {
  Module['load'] = function(f) {
    globalEval(Module['read'](f));
  };
}
if (!Module['print']) {
  Module['print'] = function(){};
}
if (!Module['printErr']) {
  Module['printErr'] = Module['print'];
}
if (!Module['arguments']) {
  Module['arguments'] = [];
}
// *** Environment setup code ***

// Closure helpers
Module.print = Module['print'];
Module.printErr = Module['printErr'];

// Callbacks
if (!Module['preRun']) Module['preRun'] = [];
if (!Module['postRun']) Module['postRun'] = [];

  {{BODY}}

  // {{MODULE_ADDITIONS}}