old_contents: /**
   * Copyright (c) 2015-present, 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 Dimensions
   * @flow
   */
  'use strict';
  
  var UIManager = require('UIManager');
  
  var invariant = require('invariant');
  
  var dimensions = UIManager.Dimensions;
  
  // We calculate the window dimensions in JS so that we don't encounter loss of
  // precision in transferring the dimensions (which could be non-integers) over
  // the bridge.
  if (dimensions && dimensions.windowPhysicalPixels) {
    // parse/stringify => Clone hack
    dimensions = JSON.parse(JSON.stringify(dimensions));
  
    var windowPhysicalPixels = dimensions.windowPhysicalPixels;
    dimensions.window = {
      width: windowPhysicalPixels.width / windowPhysicalPixels.scale,
      height: windowPhysicalPixels.height / windowPhysicalPixels.scale,
      scale: windowPhysicalPixels.scale,
      fontScale: windowPhysicalPixels.fontScale,
    };
  
    // delete so no callers rely on this existing
    delete dimensions.windowPhysicalPixels;
  }
  
  class Dimensions {
    /**
     * This should only be called from native code.
     *
     * @param {object} dims Simple string-keyed object of dimensions to set
     */
    static set(dims: {[key:string]: any}): bool {
      Object.assign(dimensions, dims);
      return true;
    }
  
    /**
     * Initial dimensions are set before `runApplication` is called so they should
     * be available before any other require's are run, but may be updated later.
     *
     * Note: Although dimensions are available immediately, they may change (e.g
     * due to device rotation) so any rendering logic or styles that depend on
     * these constants should try to call this function on every render, rather
     * than caching the value (for example, using inline styles rather than
     * setting a value in a `StyleSheet`).
     *
     * @param {string} dim Name of dimension as defined when calling `set`.
     * @returns {Object?} Value for the dimension.
     */
    static get(dim: string): Object {
      invariant(dimensions[dim], 'No dimension set for key ' + dim);
      return dimensions[dim];
    }
  }
  
  module.exports = Dimensions;
  
new_contents: /**
   * Copyright (c) 2015-present, 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 Dimensions
   * @flow
   */
  'use strict';
  
  var UIManager = require('UIManager');
  
  var invariant = require('invariant');
  
  var dimensions = UIManager.Dimensions;
  
  // We calculate the window dimensions in JS so that we don't encounter loss of
  // precision in transferring the dimensions (which could be non-integers) over
  // the bridge.
  if (dimensions && dimensions.windowPhysicalPixels) {
    // parse/stringify => Clone hack
    dimensions = JSON.parse(JSON.stringify(dimensions));
  
    var windowPhysicalPixels = dimensions.windowPhysicalPixels;
    dimensions.window = {
      width: windowPhysicalPixels.width / windowPhysicalPixels.scale,
      height: windowPhysicalPixels.height / windowPhysicalPixels.scale,
      scale: windowPhysicalPixels.scale,
      fontScale: windowPhysicalPixels.fontScale,
    };
  
    // delete so no callers rely on this existing
    delete dimensions.windowPhysicalPixels;
  }
  
  class Dimensions {
    /**
     * This should only be called from native code.
     *
     * @param {object} dims Simple string-keyed object of dimensions to set
     */
    static set(dims: {[key:string]: any}): bool {
      Object.assign(dimensions, dims);
      return true;
    }
  
    /**
     * Initial dimensions are set before `runApplication` is called so they should
     * be available before any other require's are run, but may be updated later.
     *
     * Note: Although dimensions are available immediately, they may change (e.g
     * due to device rotation) so any rendering logic or styles that depend on
     * these constants should try to call this function on every render, rather
     * than caching the value (for example, using inline styles rather than
     * setting a value in a `StyleSheet`).
     *
     * Example: `var {height, width} = Dimensions.get('window');`
     *
     * @param {string} dim Name of dimension as defined when calling `set`.
     * @returns {Object?} Value for the dimension.
     */
    static get(dim: string): Object {
      invariant(dimensions[dim], 'No dimension set for key ' + dim);
      return dimensions[dim];
    }
  }
  
  module.exports = Dimensions;
  
subject: Add example of getting window dimensions to Dimensions docs