let foo = () => new Promise((resolve, reject) => {
let canResolve = true;
if (canResolve) {
resolve('Resolved');
} else {
reject('failed');
}
})
foo().then(data => console.log(data), reason => console.log(reason));
resolve将在promise主体执行完后调用then的第一个callback,reject调用第二个.
