getStyleProperty.js.flow

/**
 * Copyright (c) 2013-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @providesModule getStyleProperty
 * @typechecks
 */
const camelize = require("./camelize");

const hyphenate = require("./hyphenate");

function asString(value)
/*?string*/
{
  return value == null ? value : String(value);
}

function getStyleProperty(
/*DOMNode*/
node,
/*string*/
name)
/*?string*/
{
  let computedStyle; // W3C Standard

  if (window.getComputedStyle) {
    // In certain cases such as within an iframe in FF3, this returns null.
    computedStyle = window.getComputedStyle(node, null);

    if (computedStyle) {
      return asString(computedStyle.getPropertyValue(hyphenate(name)));
    }
  } // Safari


  if (document.defaultView && document.defaultView.getComputedStyle) {
    computedStyle = document.defaultView.getComputedStyle(node, null); // A Safari bug causes this to return null for `display: none` elements.

    if (computedStyle) {
      return asString(computedStyle.getPropertyValue(hyphenate(name)));
    }

    if (name === 'display') {
      return 'none';
    }
  } // Internet Explorer


  if (node.currentStyle) {
    if (name === 'float') {
      return asString(node.currentStyle.cssFloat || node.currentStyle.styleFloat);
    }

    return asString(node.currentStyle[camelize(name)]);
  }

  return asString(node.style && node.style[camelize(name)]);
}

module.exports = getStyleProperty;