getMongoData.js – Wrong handling of strings that look like dates

[drmirror]

In getMongoData.js, any string that is parseable as an ISODate is converted into { $date : ... } in the output. This is wrong, I am in fact seeing fields that contain arbitrary alphanumeric codes being converted into $date notation. This is apparently done by this section in the code:

// For use in JSON.stringify to properly serialize known types
function jsonStringifyReplacer(k, v){
    if (v instanceof ObjectId)
        return { "$oid" : v.valueOf() };
    if (v instanceof NumberLong)
        return { "$numberLong" : longmangle(v) };
    if (v instanceof NumberInt)
        return v.toNumber();
    // For ISODates; the $ check prevents recursion
    if (typeof v === "string" && k.startsWith('$') == false){
        try {
            iso = ISODate(v);
            return { "$date" : iso.valueOf() };
        }
        // Nothing to do here, we'll get the return at the end
        catch(e) {}
    }
    return v;
}

Actually, I don't think it's right to parse strings into ISODates at all here, but I don't understand the overall logic well enough. Intuitively, I would think that v instanceof ISODate should suffice here.