Alternative writing methods for defining methods in Javascript (methods to define js objects in batches)_javascript skills

Copy code The code is as follows:

isArray : function(v){
return toString.apply( v) === '[object Array]';
},
isDate : function(v){
return toString.apply(v) === '[object Date]';
},
isObject : function(v){
return !!v && Object.prototype.toString.call(v) === '[object Object]';
},
isPrimitive : function(v){
return Ext.isString(v) || Ext.isNumber(v) || Ext.isBoolean(v);
},
isFunction : function(v){
return toString.apply(v) === '[object Function]';
},
isNumber : function(v){
return typeof v === 'number' && isFinite(v);
},
isString : function(v){
return typeof v === 'string';
},
isBoolean : function(v){
return typeof v = == 'boolean';
}

The above is the code to determine the type in Extjs3.X ext-base.js. If you look carefully, you will find that there are many similar things, such as :

Copy code The code is as follows:

is type: function(v){
return toString.apply(v) ==="Type";
}
or
is type: function(v){
returntypeof v ==="Type";
}

However, for tyoeof inside, we can use the toString method to determine the type. All the above codes can be of the same type, that is:

Copy Code The code is as follows:

var is type=function(v){
return toString.call(v) ==="type";
}

The above is a model, and the method corresponding to this judgment is a method. We can simplify it (but there is a drawback: poor readability), which can greatly reduce the code. This can improve Javascript loading efficiency. The improved code is as follows:

Copy code The code is as follows:

var Easy={}, dataTypes = ["Number", "Boolean", "String", "Array",
"Object", "Function", "Date", "RegExp"];
var toStr = Object.prototype.toString;
var is = function (v, t) {
return toStr(o) == "[object " t "]";
};
for ( var i = 0, len = dataTypes.length, t; i (function (t) {
Easy["is" t] = function (o) {
return is(o, t);
}
})(dataTypes[i]);//Using closure
}

For the above code, we will The Easy object has created 8 methods that start with is to determine the type; of course, if some methods are unreasonable, you can also override them, such as:

Copy code The code is as follows:

Easy.isNumber=function(v){
return toString.call(v) ==="[object Number]"&& isFinite(v);
}

So sometimes you can consider this writing method when writing some methods with similar functions. I am hungry and went to eat. I will introduce it here this time. I will talk about it next time.