I have the following javascript code written to run in node.js:
const fs = require("fs");
const path = require("path");
var copy = function(paramSource, paramDestination, paramCallback) {
if (fs.existsSync(paramDestination)) {
return paramCallback("Destination Exists"); //TODO make formal error code
} else {
fs.lstat(paramSource, function(error, sourceStats) {
if (error) {
return paramCallback(error);
} else {
if (sourceStats.isDirectory()) {
fs.readdir(paramSource, function(error, sourceContents) {
if (error) {
return paramCallback(error);
} else {
fs.mkdir(paramDestination, sourceStats.mode, function(error) {
if (error) {
paramCallback(error);
} else {
if (sourceContents.length > 0) {
sourceContents.forEach(function(sourceChild) {
copy(path.join(paramSource, sourceChild), path.join(paramDestination, sourceChild), paramCallback);
});
}
return paramCallback(null, paramDestination);
}
});
}
});
} else {
var sourceFile = fs.createReadStream(paramSource);
var destinationFile = fs.createWriteStream(paramDestination); //TODO permissions
sourceFile.on("error", function(error) {
return paramCallback(error);
});
destinationFile.on("error", function(error) {
return paramCallback(error);
});
sourceFile.on("close", function() {
//return paramCallback(null, paramSource);
});
destinationFile.on("close", function() {
return paramCallback(null, paramDestination);
});
sourceFile.pipe(destinationFile);
}
}
});
}
};
var entities = 0;
copy("/home/fatalkeystroke/testing/directory_01", "/home/fatalkeystroke/testing/directory_01_copy", function(error, name) {
if (error) {
console.log(error);
} else {
console.log(name);
entities++;
}
});
console.log("Copied " + entities + " entities.");
console.log("Program Done.");
It's a testing exerpt from an application I'm working on. I would like to keep the asynchronous nature of the copy() function, however I also want a way to know when the full copy is complete (as the code related to entities
implies). The reasoning is because I want to be able to tell when it's done of course, but also implement a progress tracking capability.
Is there a way to synchronously wait for the completion of an asynchronous function in Javascript?
via FatalKeystroke
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