I have this code:
log.error(r.reason) for r in results when r.state == 'rejected'
which translates into:
var r, _i, _len, _results;
_results = [];
for (_i = 0, _len = results.length; _i < _len; _i++) {
r = results[_i];
if (r.state === 'rejected') {
_results.push(log.error(r.reason));
}
}
return _results;
I do not need to accumulate the results of log.error, I just need to print an error for each appropriate element of the array. How is this done in coffeescript?
Almost every statement in CoffeeScript is an expression. For loops, this implies accumulating the result of each iteration in an array. If you do not want that behavior, you must explicitly add a return statement:
log.error(r.reason) for r in results when r.state == 'rejected'; return
In addition, in order to answer to your question title: "invoke function for each element in array" if your JS runtime supports the array function forEach, this is an alternative way to apply a function on every array item:
results.forEach (item) -> log.error item.reason if item.state == 'rejected'
map when you're iterating rather than mapping? Wouldn't results.filter(...).forEach(...) make more sense if you're doing it with iterators?
forEach is the right answer.