IE8 Date is not mapped

[lagoasoft-lucasschmidt]

Hey guys, I noticed some issues in a few applications of mine, when users were using IE-8.

If I try to do a ko.mapping.toJS of an object that contains an observable property of a date, it would result in a {} empty object.

Fiddle: https://jsfiddle.net/gqsekzvp/3/

You cant actually run a fiddle on IE-8, I had to paste that in my own application. I will try to find out the issue, but if you guys have any idea, let me know.

I tried with Steves version as well, so this is possibly an old bug.

[lagoasoft-lucasschmidt]

Well, I found out that the issue was that the code was failing here

    exports.getType = function(x) {
        if ((x) && (typeof (x) === "object")) {
            if (x.constructor === Date) return "date";
            if (x.constructor === Array) return "array";
        }
        return typeof x;
    };

due to the fact that we were using ES5-Shim, and somehow it was failing that code. I will have to audit here.

[crissdev]

@lucastschmidt Thanks for all the info. I tried your example in IE8 (emulated) and didn't encounter any issues. The following gist was used to test your example in an IE 11 instance emulating IE 8.

https://gist.github.com/crissdev/b5bcd8b5442f5690a130

[lagoasoft-lucasschmidt]

@crissdev , yep, as I said the issue was in the project.

We use moment.js, es5-shim. Moment was being included before es5-shim, and for some reason, when moment executed the toDate() method, it was using a different prototype of Date.

moment (default Date) > es5-shim (replaces Date) > ko mapping (checks with new Date)

I dont know technically why it happened, I would guess only if moment had an old reference to the old Date prototype, otherwise, if moment was fetching the Date prototype dynamically, it would have worked I guess.

Either way, thanks. ES5-Shim should be before everything, so I fixed that.