搜索数组的函数

Question

如何搜索嵌套数组中的元素。以下是该数组样子

arr = [ 
    ["choice1", ['a', [2, 4]], ['b', [1, 3, 4]], ['c', [3, 4]]], 
    ["choice2", ['b', [1, 4]], ['c', [1, 3]]], 
    ["choice3", ['b', [1, 2, 4]], ['c', [1, 2, 3, 4]]] 
] 

如果“A”等于“2”，那么下面的函数返回的“结果”“选择1”和“choice3”：

function arraySearch(arr, a) { 
    var result = []; 
    for(var i = 0; i < arr.length; i++) { 
     // compare each arr[i] with 'a' for the very first occurrence, and move the next array 
     if(arr[i].search(a)){ 
     result.concat(arr[0]); 
     } 
    } 
    return result; 
} 

请帮忙。提前谢谢了。