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node.js synchronize multiple actions
/*
A simple and elegant function to synchronize multiple functions that expect callback as their last parameter.
example:
sync(func1, [parms], func2, func3, func4, [parms], callback);
Public domain!!
please leave me a comment if you like it!
*/
function sync() {
var args = Array.prototype.slice.call(arguments);
var callback = args.slice(-1)[0];
args = args.slice(0,-1);
// Prep the results data set
var results = [];
var l = args.length;
for (var i = 0; i < l; i++) {
if (typeof args[i] == "function")
results.push([args[i], null, null]);
else
results[results.length-1][1] = args[i];
}
var do_nothing = false;
// handle all callbacks here
function doCallback() {
var done = true;
var result_parms = [];
results.forEach(function(value, key) {
result_parms[key] = value[2];
done = done && (value[2] !== null);
});
if (done) {
do_nothing = true;
callback(result_parms);
}
}
results.forEach(function(result, key, original) {
function cb() {
if (!do_nothing) {
result[2] = Array.prototype.slice.call(arguments);
doCallback();
}
}
process.nextTick(function() {
args = Array.prototype.slice.call(result[1]);
args.push(cb);
result[0].apply(null, args);
});
});
}
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