64 lines
1.8 KiB
JavaScript
64 lines
1.8 KiB
JavaScript
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'use strict';
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/**
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* Copyright (c) 2013-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @typechecks
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*/
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var getStyleProperty = require('./getStyleProperty');
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/**
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* @param {DOMNode} element [description]
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* @param {string} name Overflow style property name.
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* @return {boolean} True if the supplied ndoe is scrollable.
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*/
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function _isNodeScrollable(element, name) {
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var overflow = Style.get(element, name);
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return overflow === 'auto' || overflow === 'scroll';
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}
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/**
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* Utilities for querying and mutating style properties.
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*/
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var Style = {
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/**
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* Gets the style property for the supplied node. This will return either the
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* computed style, if available, or the declared style.
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*
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* @param {DOMNode} node
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* @param {string} name Style property name.
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* @return {?string} Style property value.
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*/
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get: getStyleProperty,
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/**
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* Determines the nearest ancestor of a node that is scrollable.
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*
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* NOTE: This can be expensive if used repeatedly or on a node nested deeply.
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*
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* @param {?DOMNode} node Node from which to start searching.
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* @return {?DOMWindow|DOMElement} Scroll parent of the supplied node.
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*/
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getScrollParent: function getScrollParent(node) {
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if (!node) {
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return null;
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}
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var ownerDocument = node.ownerDocument;
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while (node && node !== ownerDocument.body) {
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if (_isNodeScrollable(node, 'overflow') || _isNodeScrollable(node, 'overflowY') || _isNodeScrollable(node, 'overflowX')) {
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return node;
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}
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node = node.parentNode;
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}
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return ownerDocument.defaultView || ownerDocument.parentWindow;
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}
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};
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module.exports = Style;
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