// 具有 then 方法的对象作为参数
        const thenable = {
          then(resolve, reject) {
            console.log('then');
            // resolve('data');
            reject('reason');  // 老师下面的catch为什么捕获不了这里的错误
          }
        };
        // 因为Promise.resolve(thenable)是pending状态,所以决定不了then执行哪个回调函数.
        // 但是thenable里面的then方法会直接执行,所以执行结果的返回的Promise的状态决定了Promise.resolve(thenable).then()执行哪个回调函数
        Promise.resolve(thenable).then(
          data => console.log(data),
          err => console.log(err)
        ).catch(
            err=>console.log(err+'!')
        );
        console.log(Promise.resolve(thenable));  // Promise {<pending>}