async.map(['file1','file2','file3'], fs.stat, function(err, results){
// results is now an array of stats for each file
});
As per documentation, the second argument is:
iterator(item, callback) - A function to apply to each item in the
array.
Fine.
The iterator is passed a callback(err, transformed) which must
be called once it has completed with an error (which can be null) and
a transformed item.
I think thatfs.stat does not conform to this and I would say that this shouldn't work.
It should be something like:
async.map(['file1','file2','file3'],
function (file, complete) {
fs.stat(file, function (err, stat) {
complete(err, stat)
});
}, function(err, results){
// results is now an array of stats for each file
}
);
fs.stat accepts two parameters, the first is the file, the second is the callback, which by node convention accepts two parameters, an error and the stats of the file:
fs.stat(path, callback)
which could be seen as
fs.stat(path, function(err, stats){
// ...
});
This is why it works, fs.stat is called by passing exactly what it needs.
More info: http://nodejs.org/api/fs.html#fs_fs_stat_path_callback
From the documentation at http://nodejs.org/api/fs.html#fs_fs_stat_path_callback
fs.stat(path, callback)
Asynchronous stat(2). The callback gets two arguments (err, stats) where stats is a fs.Stats object. See the fs.Stats section below for more information.
Since the fs.stat callback returns (err, stats), the following works fine
async.map(['file1','file2','file3'], fs.stat, function(err, results){
// results is now an array of stats for each file
});
To do the same yourself pass a function which with the appropriate callback
var async = require('async')
var inspect = require('eyespect').inspector();
function custom(param, callback) {
var result = 'foo result'
var err = null
callback(err, result)
}
var items = ['item1', 'item2']
async.map(items, custom, function (err, results) {
inspect(results, 'results')
})
