封装异步的fetch，使用async await方式来使用

(async() = >{
class HttpRequestUtil {
async get(url) {
const res = await fetch(url);
const data = await res.json();
return data;
}
async post(url, data) {
const res = await fetch(url, {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify(data)
});
const result = await res.json();
return result;
}
async put(url, data) {
const res = await fetch(url, {
method: 'PUT',
headers: {
'Content-Type': 'application/json'
},
data: JSON.stringify(data)
});
const result = await res.json();
return result;
}
async delete(url, data) {
const res = await fetch(url, {
method: 'DELETE',
headers: {
'Content-Type': 'application/json'
},
data: JSON.stringify(data)
});
const result = await res.json();
return result;
}
}
const httpRequestUtil = new HttpRequestUtil();
const res = await httpRequestUtil.get('http://golderbrother.cn/');
console.log(res);
})();