ios/web/web_state/js/resources/common.js

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This file provides common methods that can be shared by other JavaScripts.

// Requires functions from base.js.

/** @typedef {HTMLInputElement|HTMLTextAreaElement|HTMLSelectElement} */
let FormControlElement;

/**
 * Namespace for this file. It depends on |__gCrWeb| having already been
 * injected. String 'common' is used in |__gCrWeb['common']| as it needs to be
 * accessed in Objective-C code.
 */
__gCrWeb.common = {};

// Store common namespace object in a global __gCrWeb object referenced by a
// string, so it does not get renamed by closure compiler during the
// minification.
__gCrWeb['common'] = __gCrWeb.common;

/**
 * JSON safe object to protect against custom implementation of Object.toJSON
 * in host pages.
 * @constructor
 */
__gCrWeb.common.JSONSafeObject = function JSONSafeObject() {};

/**
 * Protect against custom implementation of Object.toJSON in host pages.
 */
__gCrWeb.common.JSONSafeObject.prototype['toJSON'] = null;

/**
 * Retain the original JSON.stringify method where possible to reduce the
 * impact of sites overriding it
 */
__gCrWeb.common.JSONStringify = JSON.stringify;

/**
 * Returns a string that is formatted according to the JSON syntax rules.
 * This is equivalent to the built-in JSON.stringify() function, but is
 * less likely to be overridden by the website itself.  Prefer the private
 * {@code __gcrWeb.common.JSONStringify} whenever possible instead of using
 * this public function. The |__gCrWeb| object itself does not use it; it uses
 * its private counterpart instead.
 * @param {*} value The value to convert to JSON.
 * @return {string} The JSON representation of value.
 */
__gCrWeb.stringify = function(value) {
  if (value === null) return 'null';
  if (value === undefined) return 'undefined';
  if (typeof (value.toJSON) === 'function') {
    // Prevents websites from changing stringify's behavior by adding the
    // method toJSON() by temporarily removing it.
    const originalToJSON = value.toJSON;
    value.toJSON = undefined;
    const stringifiedValue = __gCrWeb.common.JSONStringify(value);
    value.toJSON = originalToJSON;
    return stringifiedValue;
  }
  return __gCrWeb.common.JSONStringify(value);
};

/**
 * Returns if an element is a text field.
 * This returns true for all of textfield-looking types such as text,
 * password, search, email, url, and number.
 *
 * This method aims to provide the same logic as method
 *     bool WebInputElement::isTextField() const
 * in chromium/src/third_party/WebKit/Source/WebKit/chromium/src/
 * WebInputElement.cpp, where this information is from
 *     bool HTMLInputElement::isTextField() const
 *     {
 *       return m_inputType->isTextField();
 *     }
 * (chromium/src/third_party/WebKit/Source/WebCore/html/HTMLInputElement.cpp)
 *
 * The implementation here is based on the following:
 *
 * - Method bool InputType::isTextField() defaults to be false and it is
 *   override to return true only in HTMLInputElement's subclass
 *   TextFieldInputType (chromium/src/third_party/WebKit/Source/WebCore/html/
 *   TextFieldInputType.h).
 *
 * - The implementation here considers all the subclasses of
 *   TextFieldInputType: NumberInputType and BaseTextInputType, which has
 *   subclasses EmailInputType, PasswordInputType, SearchInputType,
 *   TelephoneInputType, TextInputType, URLInputType. (All these classes are
 *   defined in chromium/src/third_party/WebKit/Source/WebCore/html/)
 *
 * @param {Element} element An element to examine if it is a text field.
 * @return {boolean} true if element has type=text.
 */
__gCrWeb.common.isTextField = function(element) {
  if (!element) {
    return false;
  }
  if (element.type === 'hidden') {
    return false;
  }
  return element.type === 'text' || element.type === 'email' ||
      element.type === 'password' || element.type === 'search' ||
      element.type === 'tel' || element.type === 'url' ||
      element.type === 'number';
};