多维数组转一维数组

1. [代码][JavaScript]代码    

var source = [1, ['a', 'b'], [2, ['c' ,'d']]];

function test(arr){
	var result = [];

	for(var i=0, len = arr.length;i<len;i++){
		if(Array.isArray(arr[i])){
			result = result.concat(test(arr[i]));
		}else{
			result.push(arr[i]);
		}
	}

	return result;
}

console.log(test(source));