T.array.contains判断一个数组中是否包含给定元素

// Copyright (c) 2009, Baidu Inc. All rights reserved.
// 
// Licensed under the BSD License
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//      http:// tangram.baidu.com/license.html
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 /**
 * @namespace T Tangram七巧板
 * @name T
 * @version 1.3.9
*/

/**
 * 声明baidu包
 * @author: allstar, erik, meizz, berg
 */
var T,
    baidu = T = baidu || {version: "1.3.9"}; 

//提出guid，防止在与老版本Tangram混用时
//在下一行错误的修改window[undefined]
baidu.guid = "$BAIDU$";

//Tangram可能被放在闭包中
//一些页面级别唯一的属性，需要挂载在window[baidu.guid]上
window[baidu.guid] = window[baidu.guid] || {};


/**
 * @namespace baidu.array 操作数组的方法。
 */

baidu.array = baidu.array || {};

/**
 * 查询数组中指定元素的索引位置
 * @name baidu.array.indexOf
 * @function
 * @grammar baidu.array.indexOf(source, match[, fromIndex])
 * @param {Array} source 需要查询的数组
 * @param {Any} match 买卖IC网查询项
 * @param {number} [fromIndex] 查询的起始位索引位置，如果为负数，则从source.length+fromIndex往后开始查找
 * @see baidu.array.find,baidu.array.lastIndexOf
 *             
 * @returns {number} 指定元素的索引位置，查询不到时返回-1
 */
baidu.array.indexOf = function (source, match, fromIndex) {
    var len = source.length,
        iterator = match;
        
    fromIndex = fromIndex | 0;
    if(fromIndex < 0){//小于0
        fromIndex = Math.max(0, len + fromIndex)
    }
    for ( ; fromIndex < len; fromIndex++) {
        if(fromIndex in source && source[fromIndex] === match) {
            return fromIndex;
        }
    }
    
    return -1;
};


/**
 * 买卖IC网判断一个数组中是否包含给定元素
 * @name baidu.array.contains
 * @function
 * @grammar baidu.array.contains(source, obj)
 * @param {Array} source 需要判断的数组.
 * @param {Any} obj 要查找的元素.
 * @return {boolean} 判断结果.
 * @author berg
 */
baidu.array.contains = function(source, obj) {
    return (baidu.array.indexOf(source, obj) >= 0);
};