ReactElementValidator.js

/**
 * Copyright 2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule ReactElementValidator
 */

/**
 * ReactElementValidator provides a wrapper around a element factory
 * which validates the props passed to the element. This is intended to be
 * used only in DEV and could be replaced by a static type checker for languages
 * that support it.
 */

"use strict";

var ReactElement = require('ReactElement');
var ReactPropTypeLocations = require('ReactPropTypeLocations');
var ReactCurrentOwner = require('ReactCurrentOwner');

var monitorCodeUse = require('monitorCodeUse');
var warning = require('warning');

/**
 * Warn if there's no key explicitly set on dynamic arrays of children or
 * object keys are not valid. This allows us to keep track of children between
 * updates.
 */
var ownerHasKeyUseWarning = {
  'react_key_warning': {},
  'react_numeric_key_warning': {}
};
var ownerHasMonitoredObjectMap = {};

var loggedTypeFailures = {};

var NUMERIC_PROPERTY_REGEX = /^\d+$/;

/**
 * Gets the current owner's displayName for use in warnings.
 *
 * @internal
 * @return {?string} Display name or undefined
 */
function getCurrentOwnerDisplayName() {
  var current = ReactCurrentOwner.current;
  return current && current.constructor.displayName || undefined;
}

/**
 * Warn if the component doesn't have an explicit key assigned to it.
 * This component is in an array. The array could grow and shrink or be
 * reordered. All children that haven't already been validated are required to
 * have a "key" property assigned to it.
 *
 * @internal
 * @param {ReactComponent} component Component that requires a key.
 * @param {*} parentType component's parent's type.
 */
function validateExplicitKey(component, parentType) {
  if (component._store.validated || component.key != null) {
    return;
  }
  component._store.validated = true;

  warnAndMonitorForKeyUse(
    'react_key_warning',
    'Each child in an array should have a unique "key" prop.',
    component,
    parentType
  );
}

/**
 * Warn if the key is being defined as an object property but has an incorrect
 * value.
 *
 * @internal
 * @param {string} name Property name of the key.
 * @param {ReactComponent} component Component that requires a key.
 * @param {*} parentType component's parent's type.
 */
function validatePropertyKey(name, component, parentType) {
  if (!NUMERIC_PROPERTY_REGEX.test(name)) {
    return;
  }
  warnAndMonitorForKeyUse(
    'react_numeric_key_warning',
    'Child objects should have non-numeric keys so ordering is preserved.',
    component,
    parentType
  );
}

/**
 * Shared warning and monitoring code for the key warnings.
 *
 * @internal
 * @param {string} warningID The id used when logging.
 * @param {string} message The base warning that gets output.
 * @param {ReactComponent} component Component that requires a key.
 * @param {*} parentType component's parent's type.
 */
function warnAndMonitorForKeyUse(warningID, message, component, parentType) {
  var ownerName = getCurrentOwnerDisplayName();
  var parentName = parentType.displayName;

  var useName = ownerName || parentName;
  var memoizer = ownerHasKeyUseWarning[warningID];
  if (memoizer.hasOwnProperty(useName)) {
    return;
  }
  memoizer[useName] = true;

  message += ownerName ?
    ` Check the render method of ${ownerName}.` :
    ` Check the renderComponent call using <${parentName}>.`;

  // Usually the current owner is the offender, but if it accepts children as a
  // property, it may be the creator of the child that's responsible for
  // assigning it a key.
  var childOwnerName = null;
  if (component._owner && component._owner !== ReactCurrentOwner.current) {
    // Name of the component that originally created this child.
    childOwnerName = component._owner.constructor.displayName;

    message += ` It was passed a child from ${childOwnerName}.`;
  }

  message += ' See http://fb.me/react-warning-keys for more information.';
  monitorCodeUse(warningID, {
    component: useName,
    componentOwner: childOwnerName
  });
  console.warn(message);
}

/**
 * Log that we're using an object map. We're considering deprecating this
 * feature and replace it with proper Map and ImmutableMap data structures.
 *
 * @internal
 */
function monitorUseOfObjectMap() {
  var currentName = getCurrentOwnerDisplayName() || '';
  if (ownerHasMonitoredObjectMap.hasOwnProperty(currentName)) {
    return;
  }
  ownerHasMonitoredObjectMap[currentName] = true;
  monitorCodeUse('react_object_map_children');
}

/**
 * Ensure that every component either is passed in a static location, in an
 * array with an explicit keys property defined, or in an object literal
 * with valid key property.
 *
 * @internal
 * @param {*} component Statically passed child of any type.
 * @param {*} parentType component's parent's type.
 * @return {boolean}
 */
function validateChildKeys(component, parentType) {
  if (Array.isArray(component)) {
    for (var i = 0; i < component.length; i++) {
      var child = component[i];
      if (ReactElement.isValidElement(child)) {
        validateExplicitKey(child, parentType);
      }
    }
  } else if (ReactElement.isValidElement(component)) {
    // This component was passed in a valid location.
    component._store.validated = true;
  } else if (component && typeof component === 'object') {
    monitorUseOfObjectMap();
    for (var name in component) {
      validatePropertyKey(name, component[name], parentType);
    }
  }
}

/**
 * Assert that the props are valid
 *
 * @param {string} componentName Name of the component for error messages.
 * @param {object} propTypes Map of prop name to a ReactPropType
 * @param {object} props
 * @param {string} location e.g. "prop", "context", "child context"
 * @private
 */
function checkPropTypes(componentName, propTypes, props, location) {
  for (var propName in propTypes) {
    if (propTypes.hasOwnProperty(propName)) {
      var error;
      // Prop type validation may throw. In case they do, we don't want to
      // fail the render phase where it didn't fail before. So we log it.
      // After these have been cleaned up, we'll let them throw.
      try {
        error = propTypes[propName](props, propName, componentName, location);
      } catch (ex) {
        error = ex;
      }
      if (error instanceof Error && !(error.message in loggedTypeFailures)) {
        // Only monitor this failure once because there tends to be a lot of the
        // same error.
        loggedTypeFailures[error.message] = true;
        // This will soon use the warning module
        monitorCodeUse(
          'react_failed_descriptor_type_check',
          { message: error.message }
        );
      }
    }
  }
}

var ReactElementValidator = {

  createElement: function(type, props, children) {
    // We warn in this case but don't throw. We expect the element creation to
    // succeed and there will likely be errors in render.
    warning(
      type != null,
      'React.createElement: type should not be null or undefined. It should ' +
        'be a string (for DOM elements) or a ReactClass (for composite ' +
        'components).'
    );

    var element = ReactElement.createElement.apply(this, arguments);

    // The result can be nullish if a mock or a custom function is used.
    // TODO: Drop this when these are no longer allowed as the type argument.
    if (element == null) {
      return element;
    }

    for (var i = 2; i < arguments.length; i++) {
      validateChildKeys(arguments[i], type);
    }

    if (type) {
      var name = type.displayName;
      if (type.propTypes) {
        checkPropTypes(
          name,
          type.propTypes,
          element.props,
          ReactPropTypeLocations.prop
        );
      }
      if (type.contextTypes) {
        checkPropTypes(
          name,
          type.contextTypes,
          element._context,
          ReactPropTypeLocations.context
        );
      }
    }
    return element;
  },

  createFactory: function(type) {
    var validatedFactory = ReactElementValidator.createElement.bind(
      null,
      type
    );
    validatedFactory.type = type;
    return validatedFactory;
  }

};

module.exports = ReactElementValidator;