問題描述:想通過promise對象來實現(xiàn)ajax數(shù)據(jù)請求//getDate.json{"name":"zzz","age":22,"say":"hellozzz"}//demo.jsletgetJson=url=>{letpromise=newPromise((resolve,reject)=>{letxhr=newXMLHttpRequest();xhr.open("GET",url,true);xhr.onreadystatechange=()=>{if(this.readyState!==4){return;}if(this.status==200){resolve(this.response);}else{reject(newError(this.statusText))}}xhr.responseType='json';xhr.setRequestHeader('Accept','application/json');xhr.send(null);});returnpromise;};getJson("getDate.json").then((json)=>{console.log(json);},(err)=>{console.log(err)});拋出錯誤:(intermediatevalue)isnotaconstructor