How to use timestamps and preserve insertion order in Meteor?

问题

Is it possible yet, to preserve insertion order or set reliable timestamps in Meteor given that MongoDB doesn't guarantee to return items in insertion order if no sort is specified, a document's _id is randomly generated and setting a timestamp manually on insertion would depend upon the client's clock?

回答1:

I suggest a method.

Meteor.methods({
  addItem: function (doc) {
    doc.when = new Date;
    return Items.insert(doc);
  }
});

While the client will run this locally and set when to its own current time, the server's timestamp takes priority and propagates to all subscribed clients, including the original client. You can sort on doc.when.

We'll probably add hooks for setting timestamps automatically as part of document validations and permissions.

回答2:

If you're willing to use something like these collection hooks (https://gist.github.com/matb33/5258260), along with this fancy Date.unow function (which you can safely sort on even if many documents were inserted with the same timestamp):

if (!Date.unow) {
    (function () {
        var uniq = 0;
        Date.unow = function () {
            uniq++;
            return Date.now() + (uniq % 5000);
        };
    })();
}

if (Meteor.isServer) {
    // NOTE: this isn't vanilla Meteor, and sometime in the future there may be
    // a better way of doing this, but at the time of writing this is it:
    Items.before("insert", function (userId, doc) {
        doc.created = Date.unow();
    });
}

来源：https://stackoverflow.com/questions/10465673/how-to-use-timestamps-and-preserve-insertion-order-in-meteor

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meteor