JavaScript映射 delete()方法用于从 Map 对象中删除所有元素。
delete - 语法
delete()方法由以下语法表示:
mapObj.delete()
delete - 方法示例
在这里，我们将通过各种示例来了解delete()方法。
例子1
让我们来看一个delete()方法的简单示例。
<script> var map=new Map(); map.set(1,"jQuery"); map.set(2,"AngularJS"); map.set(3,"Bootstrap"); document.writeln("Size before invoking delete() method: "+ map.size+"<br>"); map.delete(2); document.writeln("Size after invoking delete() method: "+map.size); </script>
输出:
Size before invoking delete() method: 3 Size after invoking delete() method: 2
例子2
让我们看一个确定地图对象是否包含指定元素的示例。
<script> var map=new Map(); map.set(1,"jQuery"); map.set(2,"AngularJS"); map.set(3,"Bootstrap"); document.writeln("Element present before invoking delete() method: "+ map.has(2)+"<br>"); map.delete(2); document.writeln("Element present after invoking delete() method: "+map.has(2)); </script>
输出:
Element present before invoking delete() method: true Element present after invoking delete() method: false
