我在使用ES6时遇到'this'范围问题。'this'scope with ES6 and Knockout
Here's一个链接到我original and transpiled code与BabelJS。
当调用一个函数从数组中删除一个项时,'this'的作用域是未定义的。
我怎样才能使这个没有重新定义这(let self = this)?
"use strict";
var _createClass = (function() {
function defineProperties(target, props) {
for (var i = 0; i < props.length; i++) {
var descriptor = props[i];
descriptor.enumerable = descriptor.enumerable || false;
descriptor.configurable = true;
if ("value" in descriptor) descriptor.writable = true;
Object.defineProperty(target, descriptor.key, descriptor);
}
}
return function(Constructor, protoProps, staticProps) {
if (protoProps) defineProperties(Constructor.prototype, protoProps);
if (staticProps) defineProperties(Constructor, staticProps);
return Constructor;
};
})();
function _classCallCheck(instance, Constructor) {
if (!(instance instanceof Constructor)) {
throw new TypeError("Cannot call a class as a function");
}
}
var Point = (function() {
function Point() {
var _this = this;
_classCallCheck(this, Point);
this.myArray = ko.observableArray([1, 2, 3, 4]);
this.removeFromArrayWithArrowFunction = function(value) {
_this.myArray.remove(value);
};
}
_createClass(Point, [{
key: "removeFromArray",
value: function removeFromArray(value) {
this.myArray.remove(value);
}
}]);
return Point;
})();
ko.applyBindings(new Point());
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span data-bind="text: ko.toJSON(myArray)"></span>
<h2>Issues with this scoping when using a regular Function</h2>
<ul data-bind="foreach: myArray">
<li>
<a href="#" data-bind="text: $data, click: $parent.removeFromArray"></a>
</li>
</ul>
<h2>Works as expected using an arrow function</h2>
<ul data-bind="foreach: myArray">
<li>
<a href="#" data-bind="text: $data, click: $parent.removeFromArrayWithArrowFunction"></a>
</li>
</ul>
这是不是一个真正的问题ES6,要绑定的'click'事件对象的方法。你正在失去'this'的背景。您需要将该方法绑定到父对象。 –
谢谢@JeffMercado。有关如何实现它的任何建议? –
sroes提供了一个ES6解决方案。否则,使用[这里]概述的任何方法(http://stackoverflow.com/questions/10737494/context-of-this-when-triggering-method-on-root-from-child)。 –