我在写一个使用ES2016的类,我不明白为什么,控制台向我抛出这个错误。类型调用成员方法时出现错误
我环顾四周,一个可能的原因,但:
- 它不能在函数名称的拼写错误,我已经一次又一次地检查和函数声明,我要用到的函数名调用它匹配;
highlightSelected
未与任何预先存在的属性共享其名称;- 我在
highlightSelected
函数内执行的所有操作都在作为参数传递的变量类型上被允许。
那么是怎么回事?为什么这不起作用?
Uncaught TypeError: this.highlightSelected is not a function
at HTMLAnchorElement.<anonymous> (app.js:40)
window.document.addEventListener('DOMContentLoaded', function() {
new Filter("nf");
});
class Filter {
constructor(category) {
this.products = [...document.querySelectorAll('.product')];
this.filterButtons = [...document.querySelectorAll('a.filter')];
this.lastClicked = null;
this.registerListeners();
console.log(this.filterProducts(category));
}
filterProducts(category) {
let filtered = this.products.filter(function(item) {
return (item.dataset[category] === "true");
});
return filtered;
}
registerListeners() {
this.filterButtons.map(function(button) {
button.addEventListener("click", function(event) {
console.log(event.target.dataset.cat + " has been clicked!");
if (this.lastClicked !== event.target.dataset.cat) {
this.highlightSelected(event.target)
this.lastClicked = event.target;
}
});
});
}
highlightSelected(clickedButton) {
if ((this.lastClicked !== undefined) && (this.lastClicked !== null)) {
if (this.lastClicked.classList.contains('currently-selected')) {
this.lastClicked.classList.remove('currently-selected');
}
if (!clickedButton.classList.contains('currently-selected')) {
clickedButton.classList.add('currently-selected');
}
}
}
}
html {
font-size: 16px;
}
.container {
width: 85%;
margin: 4% auto;
}
#button-area {
display: flex;
justify-content: space-around;
margin-bottom: 4rem;
}
#button-area a {
text-decoration: none;
font-family: sans-serif;
background-color: mistyrose;
color: #000;
padding: .8rem 2rem;
}
#button-area a.currently-selected {
background-color: purple;
color: white;
}
#product-area {
display: flex;
justify-content: space-around;
}
.product {
font-family: sans-serif;
font-size: 1rem;
background-color: goldenrod;
padding: .8rem 2rem;
}
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Query Selector</title>
<link rel="stylesheet" href="style.css">
</head>
<body>
<div class="container">
<div id="button-area">
<a class="filter" href="#" data-cat="ef"> Cat E </a>
<a class="filter" href="#" data-cat="lf"> Cat L </a>
<a class="filter" href="#" data-cat="gf"> Cat G </a>
<a class="filter" href="#" data-cat="nf"> Cat N </a>
</div>
<div id="product-area">
<div class="product" data-ef="true" data-lf="true" data-nf="true" data-gf="true">
<p> Car </p>
</div>
<!-- /. product -->
<div class="product" data-ef="false" data-lf="false" data-nf="false" data-gf="false">
<p> Airplane </p>
</div>
<!-- /. product -->
<div class="product" data-ef="true" data-lf="false" data-nf="false" data-gf="true">
<p> Pizza </p>
</div>
<!-- /. product -->
<div class="product" data-ef="true" data-lf="false" data-nf="false" data-gf="true">
<p> Ficus </p>
</div>
<!-- /. product -->
<div class="product" data-ef="false" data-lf="false" data-nf="true" data-gf="true">
<p> Keyboard </p>
</div>
<!-- /. product -->
<div class="product" data-ef="true" data-lf="false" data-nf="false" data-gf="false">
<p> Shirt </p>
</div>
<!-- /. product -->
<div class="product" data-ef="true" data-lf="false" data-nf="true" data-gf="true">
<p> Vanilla </p>
</div>
<!-- /. product -->
</div>
</div>
</body>
<script src="app.js"></script>
</html>
您需要将您的事件回调与类绑定。 –
由于这是ES6的标签,因此您应该使用'for ... of'而不是'map',而使用箭头函数(unbound!)'function'表达式。 – Bergi