在 JavaScript 中通过字符串调用函数并保持在作用域内

发布于 2024-08-14 11:55:35 字数 577 浏览 1 评论 0原文

我一直在玩耍和搜索，但我无法弄清楚这一点。我在 JavaScript 对象中有一个伪私有函数，需要通过 eval 调用（因为函数的名称是动态构建的）。但是，该函数通过闭包隐藏在全局范围内，我无法弄清楚如何使用 eval() 引用它。

例如：

var myObject = function(){
    var privateFunctionNeedsToBeCalled = function() {
        alert('gets here');
    };

    return {
        publicFunction: function(firstPart, SecondPart) {
            var functionCallString = firstPart + secondPart + '()';
            eval(functionCallString);
        }
    }
}();

myObject.publicFunction('privateFunctionNeeds', 'ToBeCalled');

我知道这个例子看起来很傻，但我想保持简单。有什么想法吗？

原文

I've been playing around and searching a bit, but I can't figure this out. I have a pseudo private function within a JavaScript object that needs to get called via eval (because the name of the function is built dynamically). However, the function is hidden from the global scope by a closure and I cannot figure out how to reference it using eval().

Ex:

var myObject = function(){
    var privateFunctionNeedsToBeCalled = function() {
        alert('gets here');
    };

    return {
        publicFunction: function(firstPart, SecondPart) {
            var functionCallString = firstPart + secondPart + '()';
            eval(functionCallString);
        }
    }
}();

myObject.publicFunction('privateFunctionNeeds', 'ToBeCalled');

I know the example looks silly but I wanted to keep it simple. Any ideas?

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放低过去 2024-08-21 11:55:35

传递给 eval() 的字符串在 eval() 的范围内进行计算，因此您可以这样做

    return {
        publicFunction: function(firstPart, SecondPart) {
            var captured_privateFunctionNeedsToBeCalled = privateFunctionNeedsToBeCalled;
            var functionCallString = 'captured_' + firstPart + secondPart + '()';
            eval(functionCallString);
        }
    }

但是，更好的解决方案是完全避免使用 eval() ：

var myObject = function(){
    var functions = {};
    functions['privateFunctionNeedsToBeCalled'] = function() {
        alert('gets here');
    };

    return {
        publicFunction: function(firstPart, secondPart) {
            functions[firstPart+secondPart]();
        }
    }
}();

myObject.publicFunction('privateFunctionNeeds', 'ToBeCalled');

The string passed to eval() is evaluated in that eval()'s scope, so you could do

    return {
        publicFunction: function(firstPart, SecondPart) {
            var captured_privateFunctionNeedsToBeCalled = privateFunctionNeedsToBeCalled;
            var functionCallString = 'captured_' + firstPart + secondPart + '()';
            eval(functionCallString);
        }
    }

However, a better solution would be to avoid the use of eval() entirely:

var myObject = function(){
    var functions = {};
    functions['privateFunctionNeedsToBeCalled'] = function() {
        alert('gets here');
    };

    return {
        publicFunction: function(firstPart, secondPart) {
            functions[firstPart+secondPart]();
        }
    }
}();

myObject.publicFunction('privateFunctionNeeds', 'ToBeCalled');

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