随题而学（二）多维数组转一维数组

多维数组转一维数组：[1,[2,3]] ==》 [1,2,3]

function tran(array){
if(Object.prototype.toString.call(array) != '[object Array]'){
alert(Object.prototype.toString.call(array) + "非数组")
return ;
}
var newArr = [];
function trans(arr){
for (var num = 0; num < arr.length;num ++){
if(arr[num].length){
trans(arr[num]);
} else {
newArr.push(arr[num]);
}
}
}
trans(array);
return newArr;
}

 

[javascript] 

 

op = Object.prototype,
ostring = op.toString,
...
function isFunction(it) {
return ostring.call(it) === '[object Function]';
}
function isArray(it) {
return ostring.call(it) === '[object Array]';
} 

 

Object.prototype.toString  与 typeof 区别：

typeof

在使用 typeof 运算符时采用引用类型存储值会出现一个问题，无论引用的是什么类型的对象，它都返回 "object"。

ECMA 对Object.prototype.toString的解释（http://www.ecma-international.org/ecma-262/5.1/#sec-15.2.4.2）

Object.prototype.toString ( )

When the toString method is called, the following steps are taken:

If the this value is undefined, return "[object Undefined]".
If the this value is null, return "[object Null]".
Let O be the result of calling ToObject passing the this value as the argument.
Let class be the value of the [[Class]] internal property of O.
Return the String value that is the result of concatenating the three Strings "[object ", class, and "]".

 

var oP = Object.prototype,
toString = oP.toString;
console.log(toString.call([123]));//[object Array]
console.log(toString.call('123'));//[object String]
console.log(toString.call({a: '123'}));//[object Object]
console.log(toString.call(/123/));//[object RegExp]
console.log(toString.call(123));//[object Number]
console.log(toString.call(undefined));//[object Undefined]
console.log(toString.call(null));//[object Null] 

参考：http://my.oschina.net/sfm/blog/33197，http://blog.csdn.net/spy19881201/article/details/12192767，http://www.cnblogs.com/Aralic/p/4397015.html