Add missing .bind(this)

[notwaldorf]

Not sure I understand why this is needed __computeLocalize is a function on the Polymer element, so the this inside of it is correct, and it's the element itself (it's not fired from an event or anything

[JosefJezek]

@notwaldorf this is needed for this.useKeyIfMissing

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[JosefJezek]

I signed it!

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[JosefJezek]

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[JosefJezek]

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[JosefJezek]

@notwaldorf this.useKeyIfMissing is in anonymous function...

https://github.com/StartPolymer/app-localize-behavior/blob/master/app-localize-behavior.html#L230

[JosefJezek]

I signed it!

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CLAs look good, thanks!

[sks]

@JosefJezek : Any words on the status of this PR ?

[sks]

@notwaldorf : Anything blocking from merging this PR ?

[davidrleonard]

@notwaldorf Wanted to chime in and thank you for taking the time to help us out with this issue. This fix will solve some problems for us. It seems to be linked to some deeper problems in how Polymer's template decoding code treats methods/arguments used in the template.

Here's a reproduction of the issue: https://codepen.io/davidleonard/pen/GQqGgE

When a method is defined in a Polymer element's template that takes localize as one of its arguments (e.g. <button>[[_getLabel(showFallbackLabel, localize)]]</button>), the localize function's this scope is redefined to the window. This breaks things, because the useKeyIfMissing property is defined on the element instance, not on the window. So the fallback behavior breaks here:

https://github.com/PolymerElements/app-localize-behavior/blob/6f36f0d6a57df7713df99a1aa2f350a32ef4995c/app-localize-behavior.html#L260-L271

When this.useKeyIfMissing is read, the this scope is window, so its looking for window.useKeyIfMissing. :(

This seems to be some weird but that only shows up when the localize method is used as an argument for a method in a Polymer template, not when it is called directly (e.g. <span>[[localize('FallbackLabel')]]</span>). But accepting this PR and calling .bind(this) on the anonymous function seems to solve this issue.

Thanks again, cheers!

[notwaldorf]

Eeeek sorry i dropped the ball on this folks. Looks good!

[notwaldorf]

(let me cycle the builds as a sanity check)