fetch cancel request

let controller = null;
async getData() {
    
    
// 取消请求
 controller && controller.abort();
 // 创建 AbortController 实例
const controller = new AbortController();
const list = await fetch(
'https://example.com/data',
 {
    
     signal: controller.signal
 })
 .then(res=>res.join());
console.log('list为',list);
}