JavaScript只有在某些条件为真时才允许执行各种函数 [英] JavaScript Allow various functions to execute only if some condition is true

问题描述

我有一个附加到各种元素的事件处理程序列表，但我想在某个条件为真时禁用它们的部分。这种情况（即布尔值）会动态变化，并且在变化时无法预测。以下是我目前所做的事情。

I have a list of event handlers that are attached to various elements, but I want to disable some of them when a certain condition is true. This condition (i.e. boolean value) changes dynamically and it is not predictable when it changes. Here is what I do currently.

function foo () {
    if (someCondition) {
        return;
    }

    // foo does something
}

function bar () {
    if (someCondition) {
        return;
    }

    // bar does something
}

...etc

这没关系，但在每个函数中都有if块实际上是多余的。有没有更简洁的方法来管理这个？我想知道我是否可以将两个事件处理程序附加到一个元素，并且只有在另一个元素返回true时才执行一个。

This is alright, but it's really redundant to have the if block in each function. Is there a more concise way to manage this? I was wondering if I can attach two event handlers to one element, and only execute one if the other returned true.

推荐答案

你可以编写一个函数，将函数转换为仅在条件为真时才运行的函数：

You could write a function that turns a function into one that only runs if the condition is true:

function conditionalize( fn ) {
  return function() {
    if (someCondition) return;
    return fn.apply(this, arguments);
  };
}

然后：

var foo = conditionalize(function() {
  // stuff that foo does
});

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