从“命名空间”字符串构建对象层次结构 [英] Building object hierarchy from a 'namespace' string

问题描述

我正在尝试编写一个函数，该函数接受表示命名空间的字符串（例如MyCompany.UI.LoginPage），并将命名空间的每个段定义为对象（如果它尚不存在）。例如，如果MyCompany.UI.LoginPage不是对象，它将评估此：

I'm trying to write a function that takes a string representing a namespace (e.g. "MyCompany.UI.LoginPage") and defines each segment of the namespace as an object if it doesn't already exist. For example, if "MyCompany.UI.LoginPage" wasn't an object, it would evaluate this:

MyCompany = {};
MyCompany.UI = {};
MyCompany.UI.LoginPage = {};

我想通过枚举namespace（string）参数的每个字符并定义每个对象作为枚举到达句点字符。

I would like to do this by enumerating each character of the "namespace" (string) argument and defining each object as the enumeration reaches period characters.

如何在JavaScript中枚举字符串的字符？

How can I enumerate the characters of a string in JavaScript?

推荐答案

您可以使用 String.prototype.charAt 方法：

You can access the characters of a string directly by its index, using the String.prototype.charAt method:

var str = "foo";
for (var i = 0; i < str.length; i++) {
  alert(str.charAt(i));
}

但我认为你不想遍历名称空间字符串逐个字符，您可以使用 String.prototype.split 方法，使用点（。命名空间级别的数组c $ c>）字符作为分隔符，例如：

But I don't think that you want to traverse your namespace string character by character, you can use the String.prototype.split method, to get an array containing the namespace levels using the dot (.) character as a separator, e.g.:

var levels = "MyCompany.UI.LoginPage".split('.');
// levels is an array: ["MyCompany", "UI", "LoginPage"]

但是我认为你的问题进一步到这个，我会给你一个更高级的起点，我做了一个递归函数，它将允许你完全按照自己的意愿，初始化几个嵌套使用字符串的对象级别：

But I think your question goes further to this, and I will give you a more advanced starting point, I made a recursive function that will allow you to do exactly what you want, initialize several nested object levels using a string:

用法：

initializeNS('MyCompany.UI.LoginPage');
// that will create a MyCompany global object

// you can use it on an object to avoid globals also
var topLevel = {};
initializeNS('Foo.Bar.Baz', topLevel);

// or
var One = initializeNS('Two.Three.Four', {});

实施：

function initializeNS(ns, obj) {
  var global = (function () { return this;})(), // reference to the global object
      levels = ns.split('.'), first = levels.shift();
  obj = obj || global; //if no object argument supplied declare a global property
  obj[first] = obj[first] || {}; // initialize the "level"
  if (levels.length) { // recursion condition
    initializeNS(levels.join('.'), obj[first]);
  }
  return obj[first]; // return a reference to the top level object
}

你必须改进这个函数，例如你需要清理字符串......

You will have to improve this function, for example you will need to sanitize the string...

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