javascript - 当我将其名称作为字符串时如何执行私有(private) JavaScript 函数

Question

我正在尝试从返回的对象中执行私有(private)函数。如果我提前知道函数的名称，这很容易，但在这种情况下，我不知道有哪些函数可用。我所拥有的是一个字符串，其中包含要调用的函数的名称。有没有办法通过字符串调用这些函数？

function foo() {

  // some misc. chunk of valid javascipt code
  function bar() {
      console.log("hello");
  }
  // end misc. code

  // I would like to avoid doing this if I don't have to
  var executableFn = {};
  executableFn.test = function() {
    bar();
  }
  // end

  return {
    // This works but requires I know the name of the funciton ahead of time.
    // All I have is a string name of the function to call.
    funcRunner0: function() {
      bar();
    }, 
    // My ideal method for calling but does not work
    funcRunner1: function(functionName) {
      foo[functionName]();
    }, 
    // This works but I'm trying to avoid eval.  I'm not sure if this is not so bad
    funcRunner2: function(functionName) {
      var func = eval(functionName);
      func();
    },
    // This works.  I'm not sure if this is worse than funcRunner2 or the same;
    funcRunner3: function(functionName) {
      eval(functionName + "()");
    },
    // This works but requires the executableFn object which I would like to avoid if at all possible.
    funcRunner4: function(functionName) {
      executableFn[functionName]();
    }, 
  };
}

var bas = foo();

// This works but assumes I know the name of the function to call which I don't. 
bas.funcRunner0();
// This doesn't work
bas.funcRunner1("bar");
// This works
bas.funcRunner2("bar");
// This works
bas.funcRunner3("bar");
// This works but is not my ideal
bas.funcRunner4("test");

这些是我想出的调用此函数的所有方法。你认为我用字符串调用 bar 函数的最佳方式是什么？感谢您的帮助。

Answer 1

My ideal method for calling but does not work

foo[functionName]();

是的，它试图访问 foo 函数的 [public] 属性。例如，它可以与 "call" 方法一起使用。

This works but I'm trying to avoid eval. I'm not sure if this is not so bad

var func = eval(functionName);
func();

This works. I'm not sure if this is worse than funcRunner2 or the same;

eval(functionName + "()");

从 eval 的 Angular 来看，两者都一样糟糕。选项 1 只是让使用参数变得更容易 [不需要动态评估]。

This works but requires the exec object which I would like to avoid if at all possible.

exec[functionName]();

这就是实现它的方法。由于 exec 是 foo 范围内的局部变量，您甚至拥有自己的隐私。看来你也为 publicObj 切换了 exec

// I would like to avoid doing this if I don't have to
var publicObj = {};
publicObj.test = function() {
    bar();
}

publicObj 变量，尽管它的名字，不是公开的——它是用 var 关键字声明的局部变量!顺便说一句，您可以将其简化为

var exec = {
    test: bar
};