Asynchronous javascript code with different paradigms

Article about that (ru).

Synchronous style

• [-] No parallelism.
• [-] Can not be isomorphic in general.
• [-] Expansive stack trace.
• [+] Very easy logic.
• [+] Easy to support.
• [+] Informative stack trace.
• [+] Fast (4ms).

TypeError: Cannot read property 'name' of null
    at Object.module.exports.getName (./user.js:13:23)
    at Object.module.exports.say (./greeter.js:2:41)
    at Object.<anonymous> (./index.js:7:13)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:456:32)
    at tryModuleLoad (module.js:415:12)
    at Function.Module._load (module.js:407:3)
    at Function.Module.runMain (module.js:575:10)
    at startup (node.js:160:18)

Start

npm test

Logic

Controller (index.js) gets user info from model (user.js) and calls view (greeter.js) to talk with user.

Asynchronous

Logic

We want to load user info asynchronously. Let's do it with..

NodeJS style

• [-] Non clear logic.
• [-] Too more code.
• [-] Need to rewrite all functions.
• [-] Hard to support.
• [-] Hard parallelism.
• [-] Non informative stack trace.
• [-] Slow (6ms).
• [+] Can be isomorphic.

TypeError: Cannot read property 'name' of null
    at error (./user.js:31:30)
    at fs.readFile.error (./user.js:20:16)
    at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:439:3)

Promises style

• [-] Need to rewrite all functions.
• [-] Hard to support.
• [-] Non informative stack trace.
• [-] Slow (7ms).
• [+] Easy parallelism.
• [+] Can be isomorphic.

More info

TypeError: Cannot read property 'name' of null
    at getConfig.then.config (./user.js:19:22)

Generators&co style

• [-] Need to rewrite all functions.
• [-] Can not be isomorphic (required generators support).
• [-] Non informative stack trace.
• [-] Slow (7ms).
• [+] Easy to support.
• [+] Easy parallelism.

More info

TypeError: Cannot read property 'name' of null
    at Object.<anonymous> (./user.js:18:33)
    at next (native)
    at onFulfilled (./node_modules/co/index.js:65:19)

Async/await transformed to generators by Babel

• [-] Need to rewrite all functions.
• [-] Can not be isomorphic (required generators support).
• [-] Expansive stack trace.
• [-] Non informative stack trace.
• [-] Very slow (25ms).
• [+] Easy to support.
• [+] Easy parallelism.

More info

TypeError: Cannot read property 'name' of null
    at Object.<anonymous> (user.js:18:12)
    at undefined.next (native)
    at step (C:\proj\async-js\user.js:1:253)
    at C:\proj\async-js\user.js:1:430

Fibers style

• [-] Can not be isomorphic (NodeJS only).
• [-] Slow (6ms).
• [*] Need to start application in fiber.
• [+] Need not to rewrite all funcitons.
• [+] Easy to support.
• [+] Informative stack trace.
• [+] Easy parallelism.

More info

TypeError: Cannot read property 'name' of null
    at Object.module.exports.getName (./user.js:14:23)
    at Object.module.exports.say (./greeter.js:2:41)
    at Future.task.error (./index.js:11:17)
    at ./node_modules/fibers/future.js:467:21

Atoms style

• [-] Need to convert application from control-flow to data-flow.
• [-] Expansive stack trace.
• [-] Very slow (25ms).
• [*] Medium to support.
• [+] Need not to rewrite all funcitons.
• [+] Easy parallelism.
• [+] Can be isomorphic.
• [+] Informative stack trace.

More info (russian)

TypeError: Cannot read property 'name' of null
    at Object.module.exports.getName (./user.js:22:24)
    at Object.module.exports.say (./greeter.js:2:41)
    at $mol_atom.Atom [as handler] (./index.js:9:13)
    at $mol_atom.pull (./node_modules/atom.ts:137:17)
    at $mol_atom.actualize (./node_modules/atom.ts:126:23)
    at $mol_atom.get (./node_modules/atom.ts:75:9)
    at Function.$mol_atom.sync (./node_modules/atom.ts:328:34)
    at $mol_defer.run (./node_modules/atom.ts:314:11)
    at Function.$mol_defer.run (./defer/defer.ts:53:67)
    at Timeout._onTimeout (./defer/defer.ts:28:11)

Comparison

Property	Sync	NodeJS	Promises	Generators	Async + Babel	Fibers	Atoms
Execution time on V8	4 ms	6 ms	7 ms	7 ms	25 ms	6 ms	25 ms
Parallelism	no	hard	easy	easy	easy	easy	easy
Isomorphism	some api	yes	yes	some vm	some vm	no	yes
Expansive stack	yes	no	no	no	no	no	yes
Informative stack	yes	no	no	no	no	yes	yes
Complexity of use	easy	hard	hard	easy	easy	easy	easy
Complexity of debug	easy	hard	hard	hard	hard	easy	easy