如何使用currying函数删除事件侦听器

Question

我很难删除事件侦听器类型的currying函数。

// I register first, at some time I want to remove using freezeHighlight but it doesn't working (without currying function it's working like a charm)
const privateMethods = {
  highlighted (index) {
    return function (event) {
      event.target.setAttribute('filter', 'url(#glow)')

      // need param index later
    }
  }
}

register (node, index) {
      node.addEventListener('mouseover', privateMethods.highlighted(index))
  }

freezeHighlight (node) {
        node.removeEventListener('mouseover', privateMethods.highlighted)
  }

是否可以删除事件侦听器类型的currying函数，或者我应该采取解决方法？

Answer 1

您需要记住您创建的处理程序，以便以后将其删除。

const handlers = {};

const privateMethods = {
  highlighted (index) {
    // return the saved handler if we've been called before
    // or create a new handler, save it, and return it.
    return handlers[index] || (handlers[index] = function (event) {
      event.target.setAttribute('filter', 'url(#glow)')

      // need param index later
    });
  }
}

register (node, index) {
      // add the handler
      node.addEventListener('mouseover', privateMethods.highlighted(index))
}

freezeHighlight (node, index) {
      // will remove the handler
        node.removeEventListener('mouseover', privateMethods.highlighted(index))
}

Answer 2

Columns=

您认为var listener register (node, index) { listener = privateMethods.highlighted(index) node.addEventListener('mouseover', ) } freezeHighlight (node) { node.removeEventListener('mouseover', listener) } 是侦听器。不，这不对。 privateMethods.highlighted的返回值是侦听器。