Make any Node.js REPL support promises (Promises/A+).
Either use one of the included "node-promised" or "coffee-promised" executables, or setup your own REPL:
var repl = require("repl");
var promisify = require("repl-promised").promisify;
promisify(repl.start({}));
Commands that return promises will delay printing until the promise is resolved:
> Q.delay(1000).then(function() { return "output after 1 second!"; })
'output after 1 second!'
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