IE9 and export default with ES5 compile target

[KnisterPeter]

Hello,

we are using TS 1.5 and have a compile target set to ES5.
Now there is an issue with IE9 and the default keyword. Is there a way to get around this via a compiler flag? Or is this just a bug because in IE9 'default' is a reserved word?

[KnisterPeter]

Sorry, this is not a TS problem.

[KnisterPeter]

While digging deeper, this finally is a tsc problem.
When the compile target is set to ES5, module imports with a default import are transpiled to e.g. modulevar.default(). This breaks in IE9.
While it is a view chars longer the ES5 mode should product modulevar["default"]() instead for IE9 compatibility.

[danquirk]

I think #2296 covers the general issue here. Note related pull requests #2387 and #2760

[alexkrauss]

The referenced issues only cover ES3 behaviour. However, IE9 claims ES5 support, but it still does not accept modulevar.default.

Does this mean we must use ES3 to be compatible with IE9? Or could tsc output modulevar["default"] also in ES5 mode?

[KnisterPeter]

Currently you have to use ES3 to support IE9.

Alexander Krauss notifications@github.com schrieb am So., 9. Aug. 2015
22:05:

The referenced issues only cover ES3 behaviour. However, IE9 claims ES5
support, but it still does not accept modulevar.default.

Does this mean we must use ES3 to be compatible with IE9? Or could tsc
output modulevar["default"] also in ES5 mode?

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#4145 (comment)
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[andrewmurphyio]

This is seriously affecting my ability to use TS

Can I suggest a switch or tsconfig option to enable this functionality?

[mhegazy]

Can I suggest a switch or tsconfig option to enable this functionality?

use --target ES3.

[andrewmurphyio]

@mhegazy no that's not the same. That removes support for property get/set.

I need support for this and get/set.

So either "--target ES3" needs to convert property get/sets into get/set[PropertyName] or the ES5 conversion needs to do export["default"]

[KnisterPeter]

The easiest solution for your problem would be to write a babel plugin to do the transforms from es5 to es3 which you need. And then run babel on your sources after typescript did.
But that may not be the best solution.

[andrewmurphyio]

I'm sure I could

But I still think this should be addressed as an issue with typescript.

I will affect anyone that uses a default export and IE9 and the fix is easy enough - use export['default']

[c9s]

Can we add an option this?

something like enableExportDefaultQuote