如何将字符串转换为 JavaScript 函数调用? [英] How to turn a String into a JavaScript function call?

问题描述

我得到了一个字符串:

settings.functionName + '(' + t.parentNode.id + ')';

我想转换成这样的函数调用:

that I want to translate into a function call like so:

clickedOnItem(IdofParent);

这当然必须在 JavaScript 中完成.当我对 settings.functionName + '(' + t.parentNode.id + ')'; 发出警报时，似乎一切都正确.我只需要调用它会转换成的函数.

This of course will have to be done in JavaScript. When I do an alert on settings.functionName + '(' + t.parentNode.id + ')'; it seems to get everything correct. I just need to call the function that it would translate into.

图例:

settings.functionName = clickedOnItem

t.parentNode.id = IdofParent

推荐答案

眼看着我讨厌 eval，而我是 不孤单:

Seeing as I hate eval, and I am not alone:

var fn = window[settings.functionName];
if(typeof fn === 'function') {
    fn(t.parentNode.id);
}

回复@Mahan 的评论:在这种特殊情况下，settings.functionName 将是 "clickedOnItem".这将在运行时将 var fn = window[settings.functionName]; 转换为 var fn = window["clickedOnItem"]，这将获得对 的引用函数 clickedOnItem (nodeId) {}.一旦我们在变量中引用了一个函数，我们就可以通过调用变量"来调用这个函数，即 fn(t.parentNode.id)，它等于 clickedOnItem(t.parentNode.id)，这是 OP 想要的.

In reply to @Mahan's comment: In this particular case, settings.functionName would be "clickedOnItem". This would, at runtime translate var fn = window[settings.functionName]; into var fn = window["clickedOnItem"], which would obtain a reference to function clickedOnItem (nodeId) {}. Once we have a reference to a function inside a variable, we can call this function by "calling the variable", i.e. fn(t.parentNode.id), which equals clickedOnItem(t.parentNode.id), which was what the OP wanted.

更完整的例子:

/* Somewhere: */
window.settings = {
  /* [..] Other settings */
  functionName: 'clickedOnItem'
  /* , [..] More settings */
};

/* Later */
function clickedOnItem (nodeId) {
  /* Some cool event handling code here */
}

/* Even later */
var fn = window[settings.functionName]; 
/* note that settings.functionName could also be written
   as window.settings.functionName. In this case, we use the fact that window
   is the implied scope of global variables. */
if(typeof fn === 'function') {
    fn(t.parentNode.id);
}

这篇关于如何将字符串转换为 JavaScript 函数调用?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！