如何将 node 标准的回调 API 在 fibjs 内转为"同步"调用形式（一面） about fe9-interview HOT 1 OPEN

var util = require('util');
function cb_test(a, b, cb) {
    setTimeout(() => {
        cb(null, a + b);
    }, 100);
}

var fn_sync = util.sync(cb_test);
console.log(fn_sync(100, 200));

var util = require('util');
async function async_test(a, b) {
    return a + b;
}
var fn_sync = util.sync(async_test);
console.log(fn_sync(100, 200));

var util = require('util');
function async_test(a, b) {
    return new Promise(function(resolve, reject) {
        resolve(a + b);
    });
}
var fn_sync = util.sync(async_test, true);
console.log(fn_sync(100, 200));