CODEWITHSUNDEEP
javascriptmeteor
sylverfyst
sylverfyst

Reputation: 95

Meteor Session variable not storing array

I'm working on a project with search option filters and they're updated via sessions, but I'm having some issues with the session variable actually taking the array. It works fine for non-array based values, but for instance when I pass an array with RegExp objects to be used in a mongo $in selector it doesn't work as expected. The functions work fine right up until it hits Session.set() in the code snippet below so I know I have to be doing something wrong with that:

Option.prototype.update = function () {
//updates session variable if static option
if (!this.isDynamic) {
    if(Object.prototype.toString.call(this.value) === '[object Array]') {
        var temp = this.value.slice(0);
        Session.set(this.optionName, temp);
        console.log(Session.get(this.optionName));
    }
    else {
        Session.set(this.optionName, this.value);
    }
  };
};

for whatever reason instead of displaying the array with values in it, it displays [Object], and the object in that array is empty. I've read the other Overflow posts on Session variables and arrays, and simply cloning the array before passing it doesn't seem to be working. Any idea what I'm doing wrong?

Upvotes: 1

Views: 405

Answers (1)

Hubert OG
Hubert OG

Reputation: 19544

Your code is correct (although slightly convoluted). The problem is that Session only takes EJSON–able values, and regexes are not EJSON–able. From the perspective of EJSON, regex looks just like an empty object, and that's exactly what you get in the stored array. Similar problem would appear if you try to store object with custom prototype, or with private (not enumerable) properties: everything that is not serialized to EJSON is lost.

The solution here is to create your own serialization method that will work with regexes. For example, if you will always have a flat array of regexes, you could simply stringify them before storing:

var temp = _.map(this.value, function(regex) {
  return regex.toString();
});

Upvotes: 1

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