fix(deno): Add prepack for deno build

Author: AbhiPrasad

packages/deno/package.json

@@ -41,7 +41,7 @@
     "build:types": "run-s deno-types build:types:tsc build:types:bundle",
     "build:types:tsc": "tsc -p tsconfig.types.json",
     "build:types:bundle": "rollup -c rollup.types.config.mjs",
-    "build:tarball": "npm pack",
+    "build:tarball": "ts-node ./scripts/prepack.ts && npm pack",
     "circularDepCheck": "madge --circular src/index.ts",
     "clean": "rimraf build build-types build-test coverage",
     "prefix": "yarn deno-types",
@@ -55,7 +55,7 @@
     "test:types": "deno check ./build/index.mjs",
     "test:unit": "deno test --allow-read --allow-run",
     "test:unit:update": "deno test --allow-read --allow-write --allow-run -- --update",
-    "yalc:publish": "yalc publish --push --sig"
+    "yalc:publish": "ts-node ./scripts/prepack.ts && yalc publish --push --sig"
   },
   "volta": {
     "extends": "../../package.json"

packages/deno/scripts/prepack.ts

@@ -0,0 +1,160 @@
+/* eslint-disable no-console */
+
+/**
+ * This script prepares the central `build` directory for NPM package creation.
+ * It first copies all non-code files into the `build` directory, including `package.json`, which
+ * is edited to adjust entry point paths. These corrections are performed so that the paths align with
+ * the directory structure inside `build`.
+ *
+ * TODO(v9): Remove this script and change the Deno SDK to import from build/X.
+ */
+
+import * as fs from 'fs';
+import * as path from 'path';
+
+const NPM_BUILD_DIR = 'build/npm';
+const BUILD_DIR = 'build';
+
+const ASSETS = ['README.md', 'LICENSE', 'package.json', '.npmignore'];
+
+const ENTRY_POINTS = ['main', 'module', 'types', 'browser'] as const;
+const CONDITIONAL_EXPORT_ENTRY_POINTS = ['import', 'require', ...ENTRY_POINTS] as const;
+const EXPORT_MAP_ENTRY_POINT = 'exports';
+const TYPES_VERSIONS_ENTRY_POINT = 'typesVersions';
+
+const packageWithBundles = process.argv.includes('--bundles');
+const buildDir = packageWithBundles ? NPM_BUILD_DIR : BUILD_DIR;
+
+type PackageJsonEntryPoints = Record<(typeof ENTRY_POINTS)[number], string>;
+type ConditionalExportEntryPoints = Record<(typeof CONDITIONAL_EXPORT_ENTRY_POINTS)[number], string>;
+
+interface TypeVersions {
+  [key: string]: {
+    [key: string]: string[];
+  };
+}
+
+type PackageJsonExports = Partial<ConditionalExportEntryPoints> & {
+  [key: string]: Partial<ConditionalExportEntryPoints>;
+};
+
+interface PackageJson extends Record<string, unknown>, PackageJsonEntryPoints {
+  [EXPORT_MAP_ENTRY_POINT]: PackageJsonExports;
+  [TYPES_VERSIONS_ENTRY_POINT]: TypeVersions;
+}
+
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const pkgJson: PackageJson = require(path.resolve('package.json'));
+
+// check if build dir exists
+if (!fs.existsSync(path.resolve(buildDir))) {
+  console.error(`\nERROR: Directory '${buildDir}' does not exist in ${pkgJson.name}.`);
+  console.error("This script should only be executed after you've run `yarn build`.");
+  process.exit(1);
+}
+
+// copy non-code assets to build dir
+ASSETS.forEach(asset => {
+  const assetPath = path.resolve(asset);
+  if (fs.existsSync(assetPath)) {
+    const destinationPath = path.resolve(buildDir, path.basename(asset));
+    console.log(`Copying ${path.basename(asset)} to ${path.relative('../..', destinationPath)}.`);
+    fs.copyFileSync(assetPath, destinationPath);
+  }
+});
+
+// package.json modifications
+const newPackageJsonPath = path.resolve(buildDir, 'package.json');
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const newPkgJson: PackageJson = require(newPackageJsonPath);
+
+// modify entry points to point to correct paths (i.e. strip out the build directory)
+ENTRY_POINTS.filter(entryPoint => newPkgJson[entryPoint]).forEach(entryPoint => {
+  newPkgJson[entryPoint] = newPkgJson[entryPoint].replace(`${buildDir}/`, '');
+});
+
+/**
+ * Recursively traverses the exports object and rewrites all string values to remove the build directory.
+ */
+function rewriteConditionalExportEntryPoint(
+  exportsObject: Record<string, string | Record<string, string>>,
+  key: string,
+): void {
+  const exportsField = exportsObject[key];
+  if (!exportsField) {
+    return;
+  }
+
+  if (typeof exportsField === 'string') {
+    exportsObject[key] = exportsField.replace(`${buildDir}/`, '');
+    return;
+  }
+  Object.keys(exportsField).forEach(subfieldKey => {
+    rewriteConditionalExportEntryPoint(exportsField, subfieldKey);
+  });
+}
+
+if (newPkgJson[EXPORT_MAP_ENTRY_POINT]) {
+  Object.keys(newPkgJson[EXPORT_MAP_ENTRY_POINT]).forEach(key => {
+    rewriteConditionalExportEntryPoint(newPkgJson[EXPORT_MAP_ENTRY_POINT], key);
+  });
+}
+
+if (newPkgJson[TYPES_VERSIONS_ENTRY_POINT]) {
+  Object.entries(newPkgJson[TYPES_VERSIONS_ENTRY_POINT]).forEach(([key, val]) => {
+    newPkgJson[TYPES_VERSIONS_ENTRY_POINT][key] = Object.entries(val).reduce(
+      (acc, [key, val]) => {
+        const newKey = key.replace(`${buildDir}/`, '');
+        acc[newKey] = val.map(v => v.replace(`${buildDir}/`, ''));
+        return acc;
+      },
+      {} as Record<string, string[]>,
+    );
+  });
+}
+
+delete newPkgJson.scripts;
+delete newPkgJson.volta;
+delete newPkgJson.jest;
+
+// write modified package.json to file (pretty-printed with 2 spaces)
+try {
+  fs.writeFileSync(newPackageJsonPath, JSON.stringify(newPkgJson, null, 2));
+} catch (error) {
+  console.error(`\nERROR: Error while writing modified 'package.json' to disk in ${pkgJson.name}:\n`, error);
+  process.exit(1);
+}
+
+async function runPackagePrepack(packagePrepackPath: string): Promise<void> {
+  const { prepack } = await import(packagePrepackPath);
+  if (prepack && typeof prepack === 'function') {
+    const isSuccess = prepack(buildDir);
+    if (!isSuccess) {
+      process.exit(1);
+    }
+  } else {
+    console.error(`\nERROR: Could not find a \`prepack\` function in './scripts/prepack.ts' in ${pkgJson.name}.`);
+    console.error(
+      'Make sure your package-specific prepack script exports `function prepack(buildDir: string): boolean`.',
+    );
+    process.exit(1);
+  }
+}
+
+// execute package specific settings
+// 1. check if a script called `<package-root>/scripts/prepack.ts` exists
+// if yes, 2.) execute that script for things that are package-specific
+async function runPackageSpecificScripts(): Promise<void> {
+  const packagePrepackPath = path.resolve('scripts', 'prepack.ts');
+  try {
+    if (fs.existsSync(packagePrepackPath)) {
+      await runPackagePrepack(packagePrepackPath);
+    }
+  } catch (error) {
+    console.error(`\nERROR: Error while trying to load and run ./scripts/prepack.ts in ${pkgJson.name}:\n`, error);
+    process.exit(1);
+  }
+  console.log(`\nSuccessfully finished prepack commands for ${pkgJson.name}\n`);
+}
+
+void runPackageSpecificScripts();