`SyntaxError: Unexpected token` on spread attributes

[okonet]

Not sure if this is wallaby-webpack related or should be reported in wallaby-public.

Following code is failing to be parsed:

let { type, className, isSelected, ...rest } = this.props

Error message:

Failed to parse js/modules/global/EntityComponent.jsx, SyntaxError: Unexpected token (37:43)

I'm using following preprocessor:

var babelTransformer = (file) => {
  return babel.transform(file.content, {
    sourceMap: true,
    experimental: true,
    optional: ['runtime']
  });
}

[ArtemGovorov]

Object rest/spread is a proposal for ES7 (https://github.com/sebmarkbage/ecmascript-rest-spread) and wallaby currently only supports ES6. All I can suggest for now as a workaround is not to use experimental ES7 features (they may actually change in future), and use alternative ES6 features. For example, this should work (in the latest wallaby version): let [ type, className, isSelected, ...rest ] = this.props

Having said that, I'm happy to support ES7 in wallaby. Here is the current situation: babel does support some ES7 features and wallaby is using the same code parser as babel (https://github.com/babel/acorn-babel), but wallaby needs to generated instrumented code before babel preprocessor and it uses escodegen fork (https://github.com/wallabyjs/escodegen) to do that. Escodegen doesn't yet support ES7, that's the only thing required in order to support ES7 in wallaby. I am happy to accept PR requests to https://github.com/wallabyjs/escodegen with ES7 code support. What's basically required is to add a few generate functions to support ES7 AST elements, such as SpreadProperty (in your example).

[okonet]

Actually I was hoping to have webpack me covered since I use the --experimental flag in webpack config. But the webpack's loaders doesn't seem to be working either... But I guess this is how wallaby works, using it's own parser and not the webpack's processed output.

[ArtemGovorov]

Yes, wallaby has to instrument the original code, not the processed one, to provide the code coverage correctly (source maps data is not enough for doing the coverage).

[ArtemGovorov]

@okonet Now it is supported via compilers https://github.com/wallabyjs/public#compilers-setting

[okonet]

:+1: Thanks! I'll take a look