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@joewagner
Last active December 22, 2015 11:48
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Helper function to catch version errors when trying to update an Array field in a mongoose Model
// --- Dependancies ---
var _ = require('underscore');
var mongoose = require('mongoose');
// Any function that makes an update to a mongoose model that has an Array field can
// use this to catch version errors, and retry the update at most two times
var catchVersionErr = function () {
var updateFunc, callback, context, args = _.toArray(arguments);
context = args.shift();
if (!(updateFunc = args.shift())) { throw new Error('catchVersionErr: must supply a function to do update'); }
if (!(callback = args.pop())) { throw new Error('catchVersionErr: must supply a callback'); }
var _count = 0;
// Add a wrapped callback to the args Array
args.push(function () {
var err = arguments[0];
if (err instanceof mongoose.Error.VersionError && _count < 2) {
_count += 1;
return updateFunc.apply(context, args);
}
callback.apply(this, arguments);
});
updateFunc.apply(context, args);
};
@asweeney76
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I'm finding that catchVersionErr catches the err, then retries without error - which seems fine, but my doc isn't updated. Question: when the first attempt fails, is the new __v (version) retrieved and the model updated with that new version? If not, how would this work?

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