例如:fs.writeFile是异步方法
function test(){
return co(function *() {
yield (() => new Promise((resolve, reject) => {
fs.writeFile(path, '', (err) => {
if (err) return reject(err);
resolve(1);
});
}))();
return;
});
}
调用test;
co(function *() {
let res = yield test();
console.log(res);
})