好的,所以我正在研究Nodes中的一个项目,并且遇到了对象字面量键中的一个小问题,我有以下设置:
var required = { directories : { this.applicationPath : "Application " + this.application + " does not exists", this.applicationPath + "/configs" : "Application config folder does not exists", this.applicationPath + "/controllers" : "Application controllers folder does not exists", this.applicationPath + "/public" : "Application public folder does not exists", this.applicationPath + "/views" : "Application views folder does not exists" }, files : { this.applicationPath + "/init.js" : "Application init.js file does not exists", this.applicationPath + "/controllers/index.js" : "Application index.js controller file does not exists", this.applicationPath + "/configs/application.js": "Application configs/application.js file does not exists", this.applicationPath + "/configs/server.js" : "Application configs/server.js file does not exists" } }
好的,你们中的很多人都会看这个,并认为它没问题,但是编译器不断告诉我,我缺少一个:(冒号),但不是,好像+or或the .都在影响编译器。
:
+
.
现在我相信(不确定),对象文字是在编译时创建的,而不是在运行时创建的,这意味着动态变量(例如this.applicationPath和级联)将不可用
this.applicationPath
克服此类障碍而不必重写大量代码的最佳方法是什么。
您可以使用括号表示法设置动态键:
required.directories[this.applicationPath + "/configs"] = "Application config folder does not exists";
(当然,无论您在何处进行此定义,都this.applicationPath必须存在)
但是您需要this.applicationPath按键吗?您如何访问这些值?也许您可以this.applicationPath从用于访问属性的任何值中删除。
但是如果您需要它:
如果要避免重复很多代码,可以使用数组来初始化键:
var dirs = ['configs', 'controllers', ...]; var files = ['init.js', 'controllers/index.js', ...]; var required = { directories: {}, files: {} }; required.directories[this.applicationPath] = "Application " + this.application + " does not exists"; for(var i = dirs.length; i--;) { required.directories[this.applicationPath + '/' + dirs[i]] = "Application " + dirs[i] + " folder does not exists"; } for(var i = files.length; i--;) { // same here }