json-date-reviver.js

// JSON.stringify({ date: new Date() }) --> '{"date":"2019-06-20T12:29:43.288Z"}'
// JSON.parse('{"date":"2019-06-20T12:29:43.288Z"}') --> { date: "2019-06-20T12:29:43.288Z" }
// hmm..
// let's use the following function to revive our Date objects!
function jsonDateReviver(key, value) {
    // plug this regex into regex101.com to understand how it works
    // matches 2019-06-20T12:29:43.288Z (with milliseconds) and 2019-06-20T12:29:43Z (without milliseconds)
    var dateFormat = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d{1,}|)Z$/;

    if (typeof value === "string" && dateFormat.test(value)) {
        return new Date(value);
    }

    return value;
}