javascript - 如何将几个匿名 jquery 函数转换为一个命名函数？

Question

是否可以将以下四个匿名jquery函数转换为一个传递参数的函数？

这就是我所拥有的...

    dropZone.addEventListener("dragenter", this.dragEnter, false);
    dropZone.addEventListener("dragover", this.dragOver, false);
    dropZone.addEventListener("dragleave", this.dragLeave, false);
    dropZone.addEventListener("drop", this.dragDrop, false);

...

this.dragOver = function(ev) {
    ev.stopPropagation();
    ev.preventDefault();
    this.className = "dragover";
}

this.dragLeave = function(ev) {
    ev.stopPropagation();
    ev.preventDefault();
    this.className = "dragleave";
}

this.dragEnter = function(ev) {
    ev.stopPropagation();
    ev.preventDefault();
    this.className = "dragenter";
}

this.dragDrop = function(ev) {
    ev.stopPropagation();
    ev.preventDefault();
    this.className = "dragdrop";
}

我正在寻找功能类似于...的东西

    dropZone.addEventListener("dragenter", dropEvent(this,"dragenter"), false);
    dropZone.addEventListener("dragover",  dropEvent(this,"dragOver"), false);
    dropZone.addEventListener("dragleave", dropEvent(this,"dragLeave"), false);
    dropZone.addEventListener("drop",      dropEvent(this,"dragDrop"), false);

...

function dragEvent(ev, label) {
    ev.stopPropagation();
    ev.preventDefault();
    this.className = label;
}

Answer 1

您可以使用部分应用的函数来做到这一点：

function dragEvent(that, label) {
  return function(ev) {
    ev.stopPropagation();
    ev.preventDefault();
    that.className = label;
  }
}

您可以在此处阅读有关 javascript 中的部分应用程序的更多信息：http: //benalman.com/news/2012/09/partial-application-in-javascript/