//promise异步函数的请求终止

export default function markCancleble(promise){

	let hasCanceled_ = false ;

	const wrappedPromise = new Promise((resolve,reject)=>{

		// 传递过来的promise

		promise.then((val)=>{

			hasCanceled_?reject({isCanceled:true}):resolve(val)

		})

		promise.catch((err)=>{

			hasCanceled_?reject({isCanceled:true}):resolve(err)

		})

		return {

			promise:wrappedPromise,

			cancle(){

				hasCanceled_=true

			}

		}

	})

}

//useful 挂载到this中

this.cancleble =  markCancleble (fetch())

this.cancleble.promise

				.then()

				.catch()

				///

			//取消

			this.cancleble.cancle()