Breaks deferEvaluation computed bindings on IE10 with KO 3.1+

[cstigler]

Starting with Knockout v3.1, the deferred-updates plugin breaks bindings to deferEvaluation computeds on IE10. The bindings are receiving the computed function itself, instead of the value. I have no idea why.

JSFiddle demo (open in IE10): https://jsfiddle.net/cstigler/Lge05opy/1/

That demo uses the latest releases of both Knockout (3.3) and deferred-updates (the current version on master on GitHub). It's broken for me in the official IE10/Win7 virtual machine provided at modern.ie. Weirdly, while it's 100% broken in Knockout 3.3, if I compile Knockout 3.2 using closure-compiler 0.2.0, this bug will not occur. But if I compile KO 3.2 using closure-compiler 0.2.1, it's broken (the official production build is broken).

So my best guess is that the newer versions of closure-compiler are removing something from the KO internals that deferred-updates needs, in this specific case.

[mbest]

Thanks for the report. I'll take a look at this soon.

[mbest]

Fixed.

[cstigler]

@mbest Thank you! I don't totally understand how that fix works, but I'm glad you do!

[mbest]

The problem stemmed from the fact that IE10 and below don't support setting the prototype using __proto__, which means that Knockout must copy properties instead. This makes the object signatures different from browsers that do support __proto__.

[cstigler]

Cool, thanks for the explanation.