Javascript類實例

Question

我處理和的NodeJS我想不通，爲什麼我不能從另一個類函數中調用類的實例。這是我的代碼。請幫忙。

var StationDAO = require('./StationDAO.js'); 
var StationSearchCriteria = require('./StationSearchCriteria.js'); 

function GasStationService(lat, long, zoom) { 
this.latitude = lat; 
this.longitude = long; 
this.zoom = zoom; 
this.zoomToKilometers = 0.009; 

/* ......... */ 

this.minLat = function() { 
    return this.latitude - this.zoomToKilometers; 
}; 

this.minLong = function() { 
    return this.longitude - this.zoomToKilometers; 
}; 

this.maxLat = function() { 
    return this.latitude + this.zoomToKilometers; 
}; 

this.maxLong = function() { 
    return this.longitude + this.zoomToKilometers; 
}; 

this.criteria = new StationSearchCriteria(this.minLat(), this.minLong(),  this.maxLat(), this.maxLong()); 
this.conn = new StationDAO(criteria); // why this doesnt work 

Answer 1

你傳遞的標準沒有定義我假設你想通過this.criteria isntead。

this.criteria = new StationSearchCriteria(this.minLat(), this.minLong(), this.maxLat(), this.maxLong()); 
this.conn = new StationDAO(this.criteria); //this should work