Recursive Promises?
You're returning the array before you populate it.
Instead, you need to return $q.all(promises)
within the then()
callback, and return the outer promise:
return fileSystem.getFolderContents(path).then(function(entries) {
return $q.all(entries.map(function(e) {
if (e.isFile) {
// Do something
return null; // Don't wait for anything
} else {
// Do something
return walkDirectory(e.fullPath);
}
}));
});
Ivan Bacher
Updated on June 17, 2022Comments
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Ivan Bacher almost 2 years
I would like to iterate over all files located in the HTML 5 file system and have some event get started once the iteration is complete. Since this is async + promises im having a hard time trying to grasp how it should work.
I am using a angularJS and have created a service to encapsulate html 5 file system specific features.
This is the recursive function:
function walkDirectory(path) { fileSystem.getFolderContents(path) //this is the services and it returns a promise containing all files in the current folder or directory .then(function(entries) { for (var i = 0; i < entries.length; i++) { if(entries[i].isFile) { console.log("is File: " + entries[i].name); //do something with file here } else if (entries[i].isDirectory) { console.log("is Dir: " + entries[i].name); walkDirectory(entries[i].fullPath); } } }); };
ideally i would like to call the function like so, and have it return a promise which gets executed once all files have been traversed.
walkDirectory("/").then( function() { console.log(done); });
Any tips/ ideas how this can be achieved?
an idea would be to have an array of promises and add a new promise to the array for every file/directory. My attempt:
function walkDirectory(path) { var defer= $q.defer(); var promises = [defer.promise]; fileSystem.getFolderContents(path) .then(function(entries) { for (var i = 0; i < entries.length; i++) { if(entries[i].isFile) { console.log("is File: " + entries[i].name); //do something with file here defer.resolve(); promises.push(defer.promise); } else if (entries[i].isDirectory) { console.log("is Dir: " + entries[i].name); promises.push(walkDirectory(entries[i].fullPath)); } } }); return $q.all(promises); }; walkDirectory("/").then(function() { console.log("done"); });
This doesn't seem to be working since done is never displayed in the console.