STCLI-259 provide transpile

[zburke]

Replace the transpile command implemented in #259 (STCLI-224), which transpiled and bundled with help from stripes-webpack, with one that only conducts transpilation.

yarn stripes transpile
yarn stripes transpile --files ./lib

The default files value is ./src. Files are transpiled into ./dist. Sourcemaps are included. Non-compilable files (e.g. .css) are copied into the destination directory.

All dependencies and babel config files are included locally. The intent is to provide a canonical service, much as stripes-webpack has in the past, so the packages using this service do not have to worry about managing dependencies or config files.

The babel config is contained in
./lib/commands/transpile-babel.config.json:

{
  "presets": [
    ["@babel/preset-env", {
      "targets": "> 0.25%, not dead",
      // preset-env will transform dynamic exports, but we want
      // to let webpack handle those
      "exclude": ["transform-dynamic-import"]
    }],
    ["@babel/preset-flow", { "all": true }],
    ["@babel/preset-react", { "runtime": "automatic" }],
    ["@babel/preset-typescript"]
  ],
  "plugins": [
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    // when building a platform directly, i.e. outside a workspace,
    // babel complains loudly and repeatedly that when these modules are enabled:
    // * @babel/plugin-proposal-class-properties,
    // * @babel/plugin-proposal-private-methods and
    // * @babel/plugin-proposal-private-property-in-object
    // the "loose" option must be the same for all three.
    // but @babel/preset-env sets it to false for ...private-methods.
    // overriding it here silences the complaint. STRWEB-12
    ["@babel/plugin-transform-class-properties", { "loose": true }],
    ["@babel/plugin-transform-private-methods", { "loose": true }],
    ["@babel/plugin-transform-private-property-in-object", { "loose": true }],
    "@babel/plugin-transform-export-namespace-from",
    "@babel/plugin-proposal-function-sent",
    "@babel/plugin-transform-numeric-separator",
    "@babel/plugin-proposal-throw-expressions",
    "@babel/plugin-syntax-import-meta"
  ]
}

Refs STCLI-259

[github-actions]

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[zburke]

@JohnC-80 , babel config is provided here as a straight .json file, rather than a .js file extending the config exported by stripes-webpack. At the time, my thinking was ".json is the recommended way and our config doesn't do anything fancy that requires actual JS." Which is true: the config itself doesn't require JS, but having only one single config in use across all our repos is a great goal and of course does require JS.

I think the rest of this PR is straightforward, but I welcome any feedback.

[sonarqubecloud]

Quality Gate failed

Failed conditions
1 Security Hotspot
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud