Is there a way to enable the allowTopLevelThis option?

[GianlucaGuarini]

We have problems using babel 6 in our riot-compiler Is there a way to enable the allowTopLevelThis option?

[loganfsmyth]

@GianlucaGuarini As mentioned already in that other issue, but would be invalid ES6.

In ES6, JavaScript is treated in two ways, as a "script", or as a "module". Only "module"-type javascript may use import and export, and the spec dictates that this in the context of an executing "module" is undefined.

Depending on your goals, I see two options:

1. Exclude babel-plugin-transform-es2015-modules-commonjs so that the file will be transpiled more like a "script". If you don't actually need/want to allow ES6 module syntax, I'd recommend this.
2. Implement your own Babel plugin, which would hoist all the import/export declarations to the top of the file, then wrap the body of the code in an IIFE that would set the this for your specific code.

[appedemic]

Specifically for this problem, the babel-plugin-transform-es2015-modules-commonjs has introduced a plugin option "allowTopLevelThis". However, there is currently no way to pass a plugin configuration option to a preset (#2756)

Regarding your options, is there a way to exclude babel-plugin-transform-es2015-modules-commonjs from the es2015 preset? Or would it require to create a custom preset?

[GianlucaGuarini]

@loganfsmyth thanks for your answer I am just trying to find out whether babel 6 can consistently behave like the previous release using at least some options combined with its presets. Using a complicate list of presets just to solve this simple issue seems to me a bit an overkill also because this option is already there you just need to make it public somehow

[hzoo]

We have preset options now, we could add an option to modify the modules plugins.