vuepress: Generated js files have SyntaxError when enabling source map in webpack config

I confirm that this is a issue rather than a question.

Bug report

When enabling source map in the configureWebpack option, the generated js files have SyntaxErrors. Comment the devtool: "source-map" line solves the problem.

Version

1.0.0-alpha.40

Steps to reproduce

git clone https://github.com/jjyyxx/vuepress-1367-repro.git
cd vuepress-1367-repro
npm run build

What is expected?

Generate valid code.

What is actually happening?

Uncaught SyntaxError: Unexpected token } happens in app.xxx.js.

Other relevant information

Your OS: Windows 10 1809
Node.js version: v11.4.0
Browser version: Google Chrome v72.0.3626.119
Is this a global or local install? local
Which package manager did you use for the install? npm
Does this issue occur when all plugins are disabled? yes

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 15 (12 by maintainers)

Most upvoted comments

@sinchang You misused lambda.

() => {
    devtool: 'source-map'
    // "devtool:" is an unused label
    // 'source-map' is an unused string literal expression
}

It is pretty valid javascript but may not be what you what to achieve. The correct way is

() => ({
  devtool: 'source-map'
})

which returns an object and fails as exprected.

jjyyxx on Feb 28, 2019

I found that the function workaroundEmptyStyleChunk caused this problem. https://github.com/vuejs/vuepress/blob/1850be7f343e54575c64d82c4f0cedc25a9aa91c/packages/%40vuepress/core/lib/build.js#L174-L190

The hack was introduced to address this issue. This snippet prepends styleChunkContent to appChunkContent and writes it back to app.[hash].js. When building chunks without sourcemap, each chunk ends with a semicolon (always?). So the prepending operation generates valid code.

BUT, if sourcemap is configured to be generated, webpack will append a comment line to the end of each js chunk, which breaks the precondition of each chunk ends with a semicolon, leading to invalid code after prepending.

jjyyxx on Feb 28, 2019