Select 字符串全局变量，包括子属性

Question

在javascript中，我想select某个属性的名字，它存储在一个字符串中。我知道 window[someString] 是要走的路。它在someString = "somevariable"时有效，但不幸的是，我的程序也会有someobject.someproperty这样的字符串。这不起作用。

所以问题是，给定代码

someString = "one.two.three";
one = {
  two: {
    three: "This is the value that I want to get"
  }
};
// window[someString] does not work.

，如何使用someString的值得到one.two.three的值，不用使用eval？

Answer 1

使用split做递归的方法

var someString = "one.two.three";
var keys = someString.split('.');

one = {
  two: {
    three: "This is the value that I want to get"
  }
};

function getinnerProperty(object, keys) {
  var key = keys.shift();

  if (keys.length) {
    var nestedObject = object[key];
    return getinnerProperty(nestedObject, keys);
  } else {
    return object[key];
  }
}

console.log(getinnerProperty(window, keys));

Answer 2

你可以写一个函数，使用split并迭代遍历对象树：

var someString = "one.two.three";
var one = {
  two: {
    three: "This is the value that I want to get"
  }
};

function getValue(keyStr) {
  var keys = keyStr.split('.');
  var result = global;
  for (var i = 0; i < keys.length; i++) {
    result = result[keys[i]];
  }
  return result != global ? result : undefined;
}

getValue(someString);

Select 字符串全局变量，包括子属性

Select global variable by string, including sub-properties

javascript

eval

object