var observer = function (originalData) {    var newData = {};    newData.observer = {};    newData.$data = {};    for (var key in originalData) {        (function (key) {            newData.$data[key] = originalData[key];            Object.defineProperty(newData, key, {                set: function (val) {                    newData.$data[key] = val;                    this.dispatch(key, val);                },                get: function () {                    return newData.$data[key];                }            });            newData.observer[key] = [];        })(key);    }    newData.on = function (key, callback) {        newData.observer[key].push(callback);    };    newData.dispatch = function (key, val) {        for (var i in newData.observer[key]) {            newData.observer[key][i](val);        }    };    return newData;};var data = observer({age: 1, name: 'mahuan'});data.on('name', function (val) {    console.log('hello, ' + val);});data.on('age', function (val) {    console.log('oh, you are ' + val);});data.name = "mahuan";data.age = 3;

 

hello, mahuan

oh, you are 3