Imagine this scenario in node:
var output = '';
module1.on('done', function() {
output += 'aaaa';
});
module2.on('done', function() {
output += 'bbbb';
});
// ...Doing stuff...
// Assume this is inside a promise/callback and executed after both events have fired
console.log(output);
Is it possible to ever get output like aabbaabb?
No. Similar states can occur as a result of race conditions in concurrent environments, but Javascript execution in Node is inherently single-threaded. The methods will execute atomically.
This question has some excellent relevant answers
Having said that, strings are immutable (and therefore inherently thread safe) in most languages so interleaved strings like your example should be impossible anyway.
Use promises to wait until every module will finish
F.e. http://howtonode.org/promises
In every module fill variable by speecified order like (just an idea without promises):
var output = ['',''];
module1.on('done', function() {
output[0] = 'aaaa';
});
module2.on('done', function() {
output[1] = 'bbbb';
});
// ...Doing stuff...
console.log(output.join(''));
