Automated backward-compatible code with Babel

[nezed]

A lot of ES6+ syntax features like const, async/await, spread operator and etc are supported in [email protected]+.

Node.js release calendar says that maintenance of node@6 LTS was ended at may of 2019.
This means that all versions earlier node@8 become obsolete.

I'm proposing to do different code builds for legacy and actual nodejs version

[apla]

Babel is too much for this task. Modern way to me is esm +rollup + buble.

[nezed]

@apla You proposed good stack of tools, but lets highlight possible problems that we've trying to solve:

Enviroment based polyfils.

babel-preset-env has option useBuiltIns: 'usage' that produces babel to add only required polyfils. Also that polyfills based on core-js has additional runtime feature-detection which minimizes overrides of native methods.
(e.g. Promise polyfill not even included in builds for node@10, for node@6+ it included with runtime checks, and for node@0 it always enabled)

As i understand, Buble does not provides any polyfills support, just transforms.

Automatic feature detection

A lot of ES6+ are supported by nodejs for now, e.g. Object/arguments spread & rest and doesn't require transformations.
babel-preset-env allows you to set only wanted environments, and only required transformations will be applied
(e.g. const operator doesn't transforms into var when building for node@8)

Buble just transforms all known features by preconfigured list of transforms

Syntax features

A lot of code in this repo can be simplified with async/await. Babel has great support for it for many years.

Buble has interesting philosophy and good set of transform, but i dont thins that its enough.

Module bundling

This is the rich nodejs library, which does not requires bundling. All imports working pretty good, even duplicated imports are handled by nodejs itself

ES modules (Tree shaking?)

This is the project with simple file structure, and es-modules doesn't gave any benefits (except beautiful syntax).
End-user library code does not relays on a big set of dependencies, so there is nothing to drop with tree-shaking

Maintenance

Babel are stable project, with large community. It easy to setup and maintain (look at the config in this PR - its complete setup with Babel)

[codecov-io]

Codecov Report

Merging #38 into master will increase coverage by 6.4%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master      #38     +/-   ##
=========================================
+ Coverage   87.81%   94.21%   +6.4%     
=========================================
  Files           5        4      -1     
  Lines         320      294     -26     
=========================================
- Hits          281      277      -4     
+ Misses         39       17     -22

Impacted Files	Coverage Δ
src/clickhouse.js	96.22% <100%> (ø)	⬆️
src/streams.js	98.75% <0%> (-0.02%)	⬇️

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[nezed]

I've checked current setup with dummy npm publish and it looks finished (See "Tarball Contents")

▶ npm publish

> @apla/[email protected] prepublishOnly .
> npm run build


> @apla/[email protected] build /Users/nezed/projects/node-clickhouse
> rm -r lib*/; babel src -d lib --source-maps && BABEL_ENV=legacy babel src -d lib-legacy --source-maps

Successfully compiled 4 files with Babel.
Successfully compiled 4 files with Babel.
npm notice
npm notice 📦  @apla/[email protected]
npm notice === Tarball Contents ===
npm notice 1.6kB  package.json
npm notice 442B   index.js
npm notice 1.1kB  LICENSE
npm notice 8.2kB  README.md
npm notice 10.5kB lib-legacy/clickhouse.js
npm notice 21.9kB lib-legacy/clickhouse.js.map
npm notice 1.5kB  lib-legacy/parse-error.js
npm notice 2.6kB  lib-legacy/parse-error.js.map
npm notice 5.6kB  lib-legacy/process-db-value.js
npm notice 8.0kB  lib-legacy/process-db-value.js.map
npm notice 4.9kB  lib-legacy/streams.js
npm notice 10.4kB lib-legacy/streams.js.map
npm notice 9.9kB  lib/clickhouse.js
npm notice 21.9kB lib/clickhouse.js.map
npm notice 1.1kB  lib/parse-error.js
npm notice 2.6kB  lib/parse-error.js.map
npm notice 4.6kB  lib/process-db-value.js
npm notice 8.0kB  lib/process-db-value.js.map
npm notice 4.8kB  lib/streams.js
npm notice 10.4kB lib/streams.js.map
npm notice === Tarball Details ===
npm notice name:          @apla/clickhouse
npm notice version:       1.6.0
npm notice package size:  38.7 kB
npm notice unpacked size: 139.9 kB
npm notice shasum:        f5c2cc81a2c3632ccad21cb3a17b8404cd6fb90f
npm notice integrity:     sha512-j6ffxHd4k4Nkm[...]smrZBb+n5Coug==
npm notice total files:   20
npm notice
npm ERR! code E404
npm ERR! 404 Not Found - PUT https://registry.npmjs.org/@apla%2fclickhouse - Not found
npm ERR! 404
npm ERR! 404  '@apla/[email protected]' is not in the npm registry.
npm ERR! 404 You should bug the author to publish it (or use the name yourself!)