3 ms·

Now do it with error handling and recovery.

• xg15 9y ago
  Moreover, async/await allows you to preserve multiple intermediary results between async steps - which is awkward in both promises and un-nested pyramids like the OP's: (not even starting with conditions, loops and recursive calls that contain async steps...) Async/Await: async function f(a) { var b = await foo(a); var c = await bar(a, b); return baz(a, b, c); } Promises: function f(a) { var _b; return foo(a) .then(b => { _b = b; return bar(a, b); }) .then(c => baz(a, _b, c)) } Callbacks: function f(a, done) { foo(a, b => bar(a, b, c => baz(a, b, c, done))); } Callbacks untangled: function f(a, done) { var _b; foo(a, step2); function step2(b) { _b = b; bar(a, b, step3); } function step3(c) { baz(a, _b, c, done); } }
• CodeWriter23 9y ago
  <shrugs> ok function multiStepAsyncProcess() { hitServer(params, function(err) { if(err) { handleError(err); return; } multiStepAsyncProcessStep2(); }); } function multiStepAsyncProcessStep2() { hitServer(params, function(err) { ... }); }