JavaScript命名空间、函数参数类型重载的实现
突然心血来潮写的东西，可以考虑在func({arg1: xxx, arg2: xxx})不适用的情况下使用。
<!DOCTYPE html>
<html lang="zh">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<title>命名空间、参数类型重载</title>
<script type="text/javascript" src="arg-func.js"></script>
<script type="text/javascript">
(function () {
// 支持的参数类型：boolean, number, string, function, array, object，其中object类型的重载函数可被其它类型对应重载函数找不到的时候调用
var MyFuncs = {
'myNamespace.exampleFunc(string str, number num)': function (str, num) {
alert('str: ' + str + ' num: ' + num);
},
'myNamespace.exampleFunc(number num)': function (num) {
alert('num: ' + num);
},
'myNamespace.exampleFunc(array)': function (arr) {
alert('arr: ' + arr);
},
'myNamespace.exampleFunc(object)': function (obj) {
alert('object: ' + obj);
},
'myNamespace.exampleFunc()': function () {
alert('无参数重载');
}
};
ArgFunc.parse(MyFuncs);
})();
</script>
</head>
<body>
<input type="button" value="myNamespace.exampleFunc('abc',123)" onclick="myNamespace.exampleFunc('abc', 123)" /><br />
<input type="button" value="myNamespace.exampleFunc(123)" onclick="myNamespace.exampleFunc(123)" /><br />
<input type="button" value="myNamespace.exampleFunc([1,2,3])" onclick="myNamespace.exampleFunc([1, 2, 3])" /><br />
<input type="button" value="myNamespace.exampleFunc()" onclick="myNamespace.exampleFunc()" /><br />
<input type="button" value="myNamespace.exampleFunc(false)" onclick="myNamespace.exampleFunc(false)" /><br />
<input type="button" value="myNamespace.exampleFunc('abc')" onclick="myNamespace.exampleFunc('abc')" /><br />
</body>
</html>
arg-func.js:
(function () {
if (!String.prototype.trim) {
String.prototype.trim = function () {
return this.replace(/(^\s+)|(\s+$)/g, '');
};
}
var TYPE = { EMPTY: 'empty', BOOLEAN: 'boolean', NUMBER: 'number', STRING: 'string', FUNCTION: 'function', ARRAY: 'array', OBJECT: 'object' };
function getType(o) {
if (o === undefined) { return TYPE.EMPTY; }
if (o === null) { return TYPE.OBJECT; }
switch (typeof (o)) {
case TYPE.BOOLEAN: return TYPE.BOOLEAN;
case TYPE.NUMBER: return TYPE.NUMBER;
case TYPE.STRING: return TYPE.STRING;
case TYPE.FUNCTION: return TYPE.FUNCTION;
}
switch (Object.prototype.toString.call(o)) {
case '[object Array]': return TYPE.ARRAY;
default: return o ? TYPE.OBJECT : TYPE.EMPTY;
}
}
var ArgFunc = {
findFunc: function (args, funcLink) {
if (!args || args.length == 0) {
return funcLink ? funcLink._func : null;
}
if (!funcLink) {
return null;
}
var index = arguments[2] || 0;
var argType = getType(args[index]);
var func, nextFunc = funcLink[argType];
if (index + 1 < args.length) {
func = ArgFunc.findFunc(args, nextFunc, index + 1);
if (!func) {
nextFunc = funcLink[TYPE.OBJECT];
func = ArgFunc.findFunc(args, nextFunc, index + 1);
}
} else {
func = nextFunc ? nextFunc._func : null;
if (!func) {
nextFunc = funcLink[TYPE.OBJECT];
func = nextFunc ? nextFunc._func : null;
}
}
return func;
},
applyFunc: function (wrapperFunc, args) {
var funcLink = wrapperFunc._funcs;
var func = ArgFunc.findFunc(args, funcLink);
if (!func) {
throw '没有找到参数类型匹配的重载方法';
} else {
return func.apply(this, args);
}
},
analyseNamespace: function (fullName, upperNamespace) {
var namespace = upperNamespace || window;
var parts = fullName.split('.');
var name = parts.pop();
for (var i = 0, part; part = parts[i]; i++) {
if (namespace[part] === undefined) {
namespace[part] = {};
}
namespace = namespace[part];
}
return { namespace: namespace, name: name };
},
parseSingle: function (format, func, namespace) {
var lp = format.indexOf('('), rp = format.indexOf(')');
var name = format.substring(0, lp);
var argTypes = format.substring(lp + 1, rp).split(',');
for (var i = 0, len = argTypes.length; i < len; i++) {
argTypes[i] = argTypes[i].trim().split(/ +/)[0];
}
if (argTypes.length == 1 && argTypes[0].length == 0) {
argTypes.pop();
}
var nsnn = ArgFunc.analyseNamespace(name, namespace);
namespace = nsnn.namespace;
name = nsnn.name;
var wrapperFunc = namespace[name];
if (wrapperFunc === undefined) {
wrapperFunc = namespace[name] = function () {
return ArgFunc.applyFunc(wrapperFunc, arguments);
};
wrapperFunc._funcs = {};
}
var funcLink = wrapperFunc._funcs;
for (var i = 0, argType; argType = argTypes[i]; i++) {
if (funcLink[argType] === undefined) {
funcLink[argType] = { _func: null };
}
funcLink = funcLink[argType];
}
funcLink._func = func;
},
parseArray: function (funcs, namespace) {
for (var i = 0, func; func = funcs[i]; i++) {
ArgFunc.parseSingle(func[0], func[1], namespace);
}
},
parseObject: function (funcs, namespace) {
for (var format in funcs) {
ArgFunc.parseSingle(format, funcs[format], namespace);
}
}
};
ArgFunc.parseObject({
'ArgFunc.parse(object funcs, object namespace)': function (funcs, namespace) {
ArgFunc.parseObject(funcs, namespace);
},
'ArgFunc.parse(object funcs)': function (funcs) {
ArgFunc.parseObject(funcs, window);
},
'ArgFunc.parse(array funcs, object namespace)': function (funcs, namespace) {
ArgFunc.parseArray(funcs, namespace);
},
'ArgFunc.parse(array funcs)': function (funcs) {
ArgFunc.parseArray(funcs, window);
},
'ArgFunc.parse(string format, function func, object namespace)': function (format, func, namespace) {
ArgFunc.parseSingle(format, func, namespace);
},
'ArgFunc.parse(string format, function func)': function (format, func) {
ArgFunc.parseSingle(format, func);
}
});
})();
