# Yahoo! UI Library

### dom 3.0.0b1

Yahoo! UI Library > dom > selector-native.js (source view)
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    (function(Y) {
    /**
     * The selector-native module provides support for native querySelector
     * @module dom
     * @submodule selector-native
     * @for Selector
     */

    /**
     * Provides support for using CSS selectors to query the DOM
     * @class Selector
     * @static
     * @for Selector
     */

    Y.namespace('Selector'); // allow native module to standalone

    var NativeSelector = {
        _reLead: /^\s*([>+~]|:self)/,
        _reUnSupported: /!./,

        _foundCache: [],

        _supportsNative: function() {
            // whitelist and feature detection to manage
            // future implementations manually
            return ( (Y.UA.ie >= 8 || Y.UA.webkit > 525) &&
                document.querySelectorAll);
        },

        _toArray: function(nodes) { // TODO: move to Y.Array
            var ret = nodes,
                i, len;

            if (!nodes.slice) {
                try {
                    ret = Array.prototype.slice.call(nodes);
                } catch(e) { // IE: requires manual copy
                    ret = [];
                    for (i = 0, len = nodes.length; i < len; ++i) {
                        ret[i] = nodes[i];
                    }
                }
            }
            return ret;
        },

        _clearFoundCache: function() {
            var foundCache = NativeSelector._foundCache,
                i, len;

            for (i = 0, len = foundCache.length; i < len; ++i) {
                try { // IE no like delete
                    delete foundCache[i]._found;
                } catch(e) {
                    foundCache[i].removeAttribute('_found');
                }
            }
            foundCache = [];
        },

        _sort: function(nodes) {
            if (nodes) {
                nodes = NativeSelector._toArray(nodes);
                if (nodes.sort) {
                    nodes.sort(function(a, b) {
                        return Y.DOM.srcIndex(a) - Y.DOM.srcIndex(b);
                    });
                }
            }

            return nodes;
        },

        _deDupe: function(nodes) {
            var ret = [],
                cache = NativeSelector._foundCache,
                i, node;

            for (i = 0, node; node = nodes[i++];) {
                if (!node._found) {
                    ret[ret.length] = cache[cache.length] = node;
                    node._found = true;
                }
            }
            NativeSelector._clearFoundCache();
            return ret;
        },

        // allows element scoped queries to begin with combinator
        // e.g. query('> p', document.body) === query('body > p')
        _prepQuery: function(root, selector) {
            var groups = selector.split(','),
                queries = [],
                isDocRoot = (root && root.nodeType === 9),
                i, len;

            if (root) {
                if (!isDocRoot) {
                    root.id = root.id || Y.guid();
                    // break into separate queries for element scoping
                    for (i = 0, len = groups.length; i < len; ++i) {
                        selector = '#' + root.id + ' ' + groups[i]; // prepend with root ID
                        queries.push({root: root.ownerDocument, selector: selector});
                    }
                } else {
                    queries.push({root: root, selector: selector});
                }
            }

            return queries;
        },

        _query: function(selector, root, firstOnly) {
            if (NativeSelector._reUnSupported.test(selector)) {
                return Y.Selector._brute.query(selector, root, firstOnly);
            }

            var ret = firstOnly ? null : [],
                queryName = firstOnly ? 'querySelector' : 'querySelectorAll',
                result,
                queries,
                i, query;

            root = root || Y.config.doc;

            if (selector) {
                queries = NativeSelector._prepQuery(root, selector);
                ret = [];

                for (i = 0, query; query = queries[i++];) {
                    try {
                        result = query.root[queryName](query.selector);
                        if (queryName === 'querySelectorAll') { // convert NodeList to Array
                            result = NativeSelector._toArray(result);
                        }
                        ret = ret.concat(result);
                    } catch(e) {
                        Y.log('native selector error: ' + e, 'error', 'Selector');
                    }
                }

                if (queries.length > 1) { // remove dupes and sort by doc order
                    ret = NativeSelector._sort(NativeSelector._deDupe(ret));
                }
                ret = (!firstOnly) ? ret : ret[0] || null;
            }
            return ret;
        },

        _filter: function(nodes, selector) {
            var ret = [],
                i, node;

            if (nodes && selector) {
                for (i = 0, node; (node = nodes[i++]);) {
                    if (Y.Selector._test(node, selector)) {
                        ret[ret.length] = node;
                    }
                }
            } else {
                Y.log('invalid filter input (nodes: ' + nodes +
                        ', selector: ' + selector + ')', 'warn', 'Selector');
            }

            return ret;
        },

        _test: function(node, selector) {
            var ret = false,
                groups = selector.split(','),
                item,
                i, group;

            if (node && node.tagName) { // only test HTMLElements
                node.id = node.id || Y.guid();
                for (i = 0, group; group = groups[i++];) {
                    group += '#' + node.id; // add ID for uniqueness
                    item = Y.Selector.query(group, null, true);
                    ret = (item === node);
                    if (ret) {
                        break;
                    }
                }
            }

            return ret;
        }
    };

    if (Y.UA.ie && Y.UA.ie <= 8) {
        NativeSelector._reUnSupported = /:(?:nth|not|root|only|checked|first|last|empty)/;
    }

    Y.mix(Y.Selector, NativeSelector, true);

    // allow standalone selector-native module
    if (NativeSelector._supportsNative()) {
        Y.Selector.query = NativeSelector._query;
        //Y.Selector.filter = NativeSelector._filter;
        //Y.Selector.test = NativeSelector._test;
    }
    Y.Selector.test = NativeSelector._test;
    Y.Selector.filter = NativeSelector._filter;

    })(Y);

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