I read a lot about JS accessors here and figure out this gonna be good for me:
This is what I used for local fields:
TYPE_DEFAULT_VALUE= {
number: 0,
string: "",
array: [],
object: {},
};
typeOf = function (object) {
if (typeof object === "number" && isNaN(object))
return NaN;
try {
return Object.prototype.toString.call(object).slice(8, -1).toLowerCase();
}
catch(ex) {
return "N/A";
};
};
getAccessor = function(obj, key, type, defaultValue) {
if (defaultValue === undefined)
defaultValue = TYPE_DEFAULT_VALUE[type] === undefined ? null : TYPE_DEFAULT_VALUE[type];
return {
enumerable: true,
configurable: true,
get: function () {
if (obj[key] === undefined)
obj[key] = defaultValue;
return obj[key];
},
set: function (value) {
if (typeOf(value) === type)
obj[key] = value;
},
};
}
LocalFields = function (fields, object) {
/**
* field properties
* {
* type: [ required ] ( number | string | array | object | ... ),
* defaultValue: [ optional ]
* }
*/
if (! fields)
throw "Too few parameters ...";
if (! object)
object = this;
var obj = this;
var fieldsAccessor = {};
for(key in fields){
field = fields[key];
fieldHandler = key[0].toUpperCase() + key.substr(1);
if(! field.type)
throw "Type not set for field: " + key;
fieldsAccessor[fieldHandler] = getAccessor(obj, fieldHandler, field.type, field.defaultValue)
}
Object.defineProperties(object, fieldsAccessor);
}
Now for each Class I can just call something like:
Person = function(){
new LocalFields({
id: { type: "number" },
name: { type: "string" },
phone: { type: "array" },
}, this);
}
And then like VS getter and setter you'll call:
var alex = new Person();
alex.Name = "Alex Ramsi";
console.clear();
console.info(alex.Name);
this works for all types but there is a problem because getter and setter is the basic operation and what if I want to add an array field and call this append method or even prepend is there anyhow anyway to do that? For example How can I call:
alex.Phone.append('+1234567890');
That's a good effort but you forgot that there is no append function for array list! You can use push and any other array functionality. Check it again;
来源:https://stackoverflow.com/questions/30274789/javascript-beyond-property-accessors