refactor: use async fs calls in src/utils/proxy.js

[JCMais]

Describe the bug

This file could easily use the async versions of the fs functions instead of the sync ones.

Additional context

See: #1271 (comment)

[mugi111]

If you don't mind, I want to challenge to fix this issue !

[erezrokah]

Thanks @mugi111, I assigned you to the issue. Please let me know if there is anything you need.

[mugi111]

cli/src/utils/proxy.js

Line 235 in 5c9fed7

headersFiles.filter(fs.existsSync).map(p => path.relative(projectDir, p))

Let me ask for advice on how to fix this.
Is it correct to filter the headersFiles with fs.stat() and isFiles() once and then use map() for that array?

[erezrokah]

You could use https://github.com/sindresorhus/p-filter to filter promises, then run map in the result.
You can use

cli/src/lib/fs.js

Line 18 in 5c9fed7

const fileExistsAsync = async filePath => {

for the filter

[mugi111]

Thank you. It was helpful.
I'll deal with it that way.

[iChenLei]

This issue looks like solved, why still opened ?

[ehmicky]

Yes, this is solved, thanks for raising this @iChenLei 👍