如果你是个Javascript程序员，那一定经常写下面的代码：
function funcA(url, params, callback, option){
if(arguments.length == 2){
//funcA(url, callback);
if(typeof params == 'function'){
callback = params;
params = {};
}else{
//funcA(url, params);
//......
}
}else {
//......
}
}
当参数变化形式比较少的时候还没问题，当你的方法想对多种传参形式进行容错时，一堆的if else判断就变得很难看了。这时不妨尝试下这个 getArguments 方法。more
var toString = Object.prototype.toString;
var is = function(obj){
var type = toString.apply(obj);
type = type.substring(8, type.length - 1);
return type;
}
var getArguments = function(argus, type1, type2, type3 /*...*/){
var srcTypes = [];
var targetTypes = Array.prototype.slice.call(arguments, 1);
var result = [];
for(var i = 0, len = argus.length; i < len; i++) {
srcTypes.push(is(argus[i]));
}
for(var m = 0, n = 0, len = targetTypes.length; n < len; ){
if(srcTypes[m] === targetTypes[n]){
result.push(argus[m]);
m++, n++;
}else{
result.push(null);
n++;
}
}
return result;
}
使用方法如下：
function funcB(name, params, callback, option){
var argus = getArguments(arguments, 'String', 'Object', 'Function', 'Object');
name = argus[0], params = argus[1] || {}, callback = argus[2], option = argus[3] || {};
console.log(argus);
}
运行结果如下：
funcB('a',function(){})
//console: ["a", null, function, null]
funcB('a',function(){}, {o:1})
//console: ["a", null, function, Object]
funcB('a',{p:1})
//console: ["a", Object, null, null]
funcB({p:1})
//console: [null, Object, null, null]
funcB(function(){})
//console: [null, null, function, null]
怎么样，是不是简单很多咧？^_^