JavaScriptでコールバック地獄に対処する別の自転車

 "use strict"; var notifyUserFriends = function () { var _ref = _asyncToGenerator(regeneratorRuntime.mark(function _callee(user_id) { var friends, i, sent; return regeneratorRuntime.wrap(function _callee$(_context) { while (1) { switch (_context.prev = _context.next) { case 0: _context.next = 2; return getUserFriends(user_id); case 2: friends = _context.sent; i = 0; case 4: if (!(i < friends.length)) { _context.next = 14; break; } _context.next = 7; return getUser(friends[i].id); case 7: friend = _context.sent; _context.next = 10; return sendEmail(freind.email, "subject", "body"); case 10: sent = _context.sent; case 11: i++; _context.next = 4; break; case 14: case "end": return _context.stop(); } } }, _callee, this); })); return function notifyUserFriends(_x) { return _ref.apply(this, arguments); }; }(); function _asyncToGenerator(fn) { return function () { var gen = fn.apply(this, arguments); return new Promise(function (resolve, reject) { function step(key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { return Promise.resolve(value).then(function (value) { step("next", value); }, function (err) { step("throw", err); }); } } return step("next"); }); }; } 

  var SynJS = require('synjs'); var fetchUrl = require('fetch').fetchUrl; function fetch(context,url) { console.log('fetching started:', url); var result = {}; fetchUrl(url, function(error, meta, body){ result.done = true; result.body = body; result.finalUrl = meta.finalUrl; console.log('fetching finished:', url); SynJS.resume(context); } ); return result; } function myFetches(modules, urls) { for(var i=0; i<urls.length; i++) { var res = modules.fetch(_synjsContext, urls[i]); SynJS.wait(res.done); if(res.finalUrl.indexOf('github')>=0) { console.log('found correct one!', urls[i]); break; } } }; var modules = { SynJS: SynJS, fetch: fetch, }; const urls = [ 'http://www.google.com', 'http://www.yahoo.com', 'http://www.github.com', // This is the valid one 'http://www.wikipedia.com' ]; SynJS.run(myFetches,null,modules,urls,function () { console.log('done'); }); 

  global.SynJS = global.SynJS || require('synjs'); var mysql = require('mysql'); var connection = mysql.createConnection({ host : 'localhost', user : 'tracker', password : 'tracker123', database : 'tracker' }); function mysqlQueryWrapper(modules,context,query, params){ var res={}; modules.connection.query(query,params,function(err, rows, fields){ if(err) throw err; res.rows = rows; res.done = true; SynJS.resume(context); }) return res; } function getChildsWrapper(modules, context, doc_id, children) { var res={}; SynJS.run(modules.getChilds,null,modules,doc_id, children, function (ret) { res.result = ret; res.done = true; SynJS.resume(context); }); return res; } function getChilds(modules, doc_id, children) { var ret={}; console.log('processing getChilds:',doc_id,SynJS.states); var docRec = modules.mysqlQueryWrapper(modules,_synjsContext,"select * from docs where id=?",[doc_id]); SynJS.wait(docRec.done); ret.curr = docRec.rows[0]; ret.childs = []; var docLinks = modules.mysqlQueryWrapper(modules,_synjsContext,"select * from doc_links where doc_id=?",[doc_id]); SynJS.wait(docLinks.done); for(var i=0; docLinks.rows && i < docLinks.rows.length; i++) { var currDocId = docLinks.rows[i].child_id; if(currDocId) { console.log('synjs run getChilds start'); var child = modules.getChildsWrapper(modules,_synjsContext,currDocId,children); SynJS.wait(child.done); children[child.result.curr.name] = child.result.curr.name; } } return ret; }; var modules = { SynJS: SynJS, mysqlQueryWrapper: mysqlQueryWrapper, connection: connection, getChilds: getChilds, getChildsWrapper: getChildsWrapper, }; var children={}; SynJS.run(getChilds,null,modules,12,children,function (ret) { connection.end(); console.log('done',children); });