fetch

        fetch('http://localhost:3000/books', {
            method: 'post',
            body: JSON.stringify({
                uname: '张三',
                pwd: '456'
            }),
            headers: {
                'Content-Type': 'application/json'
            }
        })
            .then((data) =>{
                return data.json();
            }).then( (res)=> {
                console.log(res)
            });