Stringify stats using streaming approach

[lahmatiy]

What kind of change does this PR introduce?

This PR changes the approach for stats stringify to use stream instead of JSON.stringify() + sync write. No API or functionality is changed.

Did you add tests for your changes?

No

If relevant, did you update the documentation?

Not needed

Summary

It makes stats available for huge projects. Changes has the follow effects:

• Memory
  • Allows to avoid max string length limit of V8 engine (500MB). In other words, stats becomes available for huge projects, whose stats exceed 500MB.
  • Reduces memory consumption on serialization.
• Adds time penalty. However, this make sense for huge stats only and seems to be an acceptable, given that otherwise stats may be unavailable (due max string limit hit or out of memory).
• Adds new dependency "json-ext", which is dependency free and most effective solution for a huge JSON parse/stringify at the moment. Other solutions have troubles to handle huge JSON (see benchmark).

Does this PR introduce a breaking change?

No

Other information

Tested on AST Explorer (https://github.com/fkling/astexplorer)

Command (cwd website):

npm run build -- --json stats.json

BEFORE:

fs.writeFileSync(dest, JSON.stringify(stats.toJson(...)))

Time: 4583ms
Memory used: +1_850_027_831 (heap: +1_508_459_432, external: +341_568_399)

AFTER:

createJsonStringifyStream(stats.toJson(...)).pipe(fs.createWriteStream(dest))

Time: 5881ms
Memory used: -90_171_587 (heap: -32_339_984, external: -57_831_603)

So it's a bit slower, but much effective in memory consumption.

[TrySound]

I think node 12+ support is too optimistic until April.

[lahmatiy]

@TrySound Didn't know that requirement. Will fix it a bit later.

[anshumanv]

I've re-run the CI job, some random install failure Edit - node version incompatibility

[codecov]

Codecov Report

Merging #2190 (9b5d04e) into master (3e5f946) will increase coverage by 2.23%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #2190      +/-   ##
==========================================
+ Coverage   66.09%   68.32%   +2.23%     
==========================================
  Files          72       72              
  Lines        2345     2346       +1     
  Branches      518      518              
==========================================
+ Hits         1550     1603      +53     
+ Misses        795      743      -52     

Impacted Files	Coverage Δ
packages/webpack-cli/lib/webpack-cli.js	95.83% <66.66%> (+12.18%)	⬆️
packages/migrate/src/index.ts	90.24% <0.00%> (+4.87%)	⬆️
packages/utils/src/prop-types.ts	100.00% <0.00%> (+16.66%)	⬆️
packages/webpack-cli/lib/utils/to-kebab-case.js	100.00% <0.00%> (+33.33%)	⬆️
packages/webpack-cli/lib/utils/cli-flags.js	100.00% <0.00%> (+53.84%)	⬆️

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[lahmatiy]

Fixed, now json-ext supports Node.js 10. All tests passed

[alexander-akait]

Big thanks