wip

Author: iamstarkov

test/unit/node2020/README.md

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+# unit test drafts for node targets
+
+playground to get going on the https://github.com/vercel/ncc/issues/1247 while i get a hang of ncc test infra and how to fix node gyp issues.
+
+currently, i dont understand why webpack with node16 target compile into v into u regexp flag and why usage of Set.prototype.difference doesnt bring in core-js imports if
+
+```
+cd test/unit/node2020
+npx webpack
+```

test/unit/node2020/input.js

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+// added in es2025
+// https://babeljs.io/docs/babel-plugin-transform-regexp-modifiers
+//    const regex = /(?i:a)a/
+// output for es2024
+//    const regex = /(?:[Aa])a/
+// but throws an error:
+// Module parse failed: Invalid regular expression: /(?i:a)a/: Invalid group (3:15) You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
+
+// added in node22
+// https://nodejs.org/en/blog/announcements/v22-release-announce
+  new Set([1, 2]).intersection(new Set([2, 3])); // Set(1) { 2 }
+// output for node20
+//    import "core-js/modules/es.set.js";
+//    new Set([1, 2]).intersection(new Set([2, 3])); // Set(1) { 2 }
+// but remains unchanged with target: node16 and doesnt add core-js imports
+
+// added in es2024 + node20
+// https://babeljs.io/docs/babel-plugin-transform-unicode-sets-regex
+// https://nodejs.org/en/blog/announcements/v20-release-announce
+    /[\p{ASCII}&&\p{Decimal_Number}]/v;
+// output es2023 node20
+//    /[0-9]/u;
+// but remains unchanged with target: node16

test/unit/node2020/output.js

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+/******/ (() => { // webpackBootstrap
+// added in es2025
+// https://babeljs.io/docs/babel-plugin-transform-regexp-modifiers
+//    const regex = /(?i:a)a/
+// output for es2024
+//    const regex = /(?:[Aa])a/
+// but throws an error:
+// Module parse failed: Invalid regular expression: /(?i:a)a/: Invalid group (3:15) You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
+
+// added in node22
+// https://nodejs.org/en/blog/announcements/v22-release-announce
+  new Set([1, 2]).intersection(new Set([2, 3])); // Set(1) { 2 }
+// output for node20
+//    import "core-js/modules/es.set.js";
+//    new Set([1, 2]).intersection(new Set([2, 3])); // Set(1) { 2 }
+// but remains unchanged with target: node16 and doesnt add core-js imports
+
+// added in es2024 + node20
+// https://babeljs.io/docs/babel-plugin-transform-unicode-sets-regex
+// https://nodejs.org/en/blog/announcements/v20-release-announce
+    /[\p{ASCII}&&\p{Decimal_Number}]/v;
+// output es2023 node20
+//    /[0-9]/u;
+// but remains unchanged with target: node16
+
+/******/ })()
+;

test/unit/node2020/webpack.config.js

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+// npx webpack-cli
+// --output-path=./test/unit/node2020/
+// --output-filename=output.js
+// --target=es2022
+
+// ./test/unit/node2020/input.js
+
+module.exports = {
+  entry: './input.js',
+  mode: 'none',
+  output: {
+    path: __dirname,
+    filename: 'output.js',
+    chunkFormat: 'commonjs',
+    clean: {
+      keep(asset) {
+        return !asset.includes('output.js');
+      }
+    },
+  },
+  // target: 'es2023',
+  // target: 'browserslist: node 16',
+  target: 'node16',
+};