promise 错误尝试

        function load(onError) {
            
            const p = fetch('https://backend.chechakj.com1/api/testaa1')
            
            return p.catch(err => {
                
                return new Promise((resolve, reject) => {
                
                    const retry = () => resolve(load(onError))
                    const fail = () => reject(err)
                    onError(retry, fail)
                })
            })
        }

        let trytime = 3

        load((a, b) => {
            trytime--
            if (trytime > 0)
                a()
            else
                b()
        }).then(res => {

        }, err => {
            console.log(err)
        })