Specify runtime exports (#10853)

packages/babel-plugin-transform-runtime/scripts/build-dist.js

@@ -90,24 +90,56 @@ function writeCoreJS({
       `module.exports = require("${corejsRoot}/${corejsPath}");`
     );
   });
+
+  writeCorejsExports(pkgDirname, runtimeRoot, paths);
+}
+
+function writeCorejsExports(pkgDirname, runtimeRoot, paths) {
+  const pkgJsonPath = require.resolve(`${pkgDirname}/package.json`);
+  const pkgJson = require(pkgJsonPath);
+  const exports = pkgJson.exports;
+  // Export `./core-js/` so `import "@babel/runtime-corejs3/core-js/some-feature.js"` works
+  exports[`./${runtimeRoot}/`] = `./${runtimeRoot}/`;
+  for (const corejsPath of paths) {
+    // Export `./core-js/some-feature` so `import "@babel/runtime-corejs3/core-js/some-feature"` also works
+    const corejsExportPath = `./${runtimeRoot}/${corejsPath}`;
+    exports[corejsExportPath] = corejsExportPath + ".js";
+  }
+  pkgJson.exports = exports;
+  outputFile(pkgJsonPath, JSON.stringify(pkgJson, undefined, 2) + "\n");
 }
 
 function writeHelpers(runtimeName, { corejs } = {}) {
-  writeHelperFiles(runtimeName, { corejs, esm: false });
-  writeHelperFiles(runtimeName, { corejs, esm: true });
+  const helperPaths = writeHelperFiles(runtimeName, { corejs, esm: false });
+  const helperESMPaths = writeHelperFiles(runtimeName, { corejs, esm: true });
+  writeHelperExports(runtimeName, helperPaths.concat(helperESMPaths));
 }
 
+function writeHelperExports(runtimeName, helperPaths) {
+  const helperSubExports = {};
+  for (const helperPath of helperPaths) {
+    helperSubExports[helperPath.replace(".js", "")] = helperPath;
+  }
+  const exports = {
+    "./helpers/": "./helpers/",
+    ...helperSubExports,
+    "./package.json": "./package.json",
+    "./regenerator": "./regenerator/index.js",
+    "./regenerator/": "./regenerator/",
+  };
+  const pkgDirname = getRuntimeRoot(runtimeName);
+  const pkgJsonPath = require.resolve(`${pkgDirname}/package.json`);
+  const pkgJson = require(pkgJsonPath);
+  pkgJson.exports = exports;
+  outputFile(pkgJsonPath, JSON.stringify(pkgJson, undefined, 2) + "\n");
+}
 function writeHelperFiles(runtimeName, { esm, corejs }) {
   const pkgDirname = getRuntimeRoot(runtimeName);
-
+  const helperPaths = [];
   for (const helperName of helpers.list) {
-    const helperFilename = path.join(
-      pkgDirname,
-      "helpers",
-      esm ? "esm" : "",
-      `${helperName}.js`
-    );
-
+    const helperPath =
+      "./" + path.join("helpers", esm ? "esm" : "", `${helperName}.js`);
+    const helperFilename = path.join(pkgDirname, helperPath);
     outputFile(
       helperFilename,
       buildHelper(runtimeName, pkgDirname, helperFilename, helperName, {
@@ -115,7 +147,11 @@ function writeHelperFiles(runtimeName, { esm, corejs }) {
         corejs,
       })
     );
+
+    helperPaths.push(helperPath);
   }
+
+  return helperPaths;
 }
 
 function getRuntimeRoot(runtimeName) {
@@ -171,11 +207,7 @@ function buildHelper(
         transformRuntime,
         { corejs, useESModules: esm, version: runtimeVersion },
       ],
-      buildRuntimeRewritePlugin(
-        runtimeName,
-        path.relative(path.dirname(helperFilename), pkgDirname),
-        helperName
-      ),
+      buildRuntimeRewritePlugin(runtimeName, helperName, esm),
     ],
     overrides: [
       {
@@ -186,12 +218,19 @@ function buildHelper(
   }).code;
 }
 
-function buildRuntimeRewritePlugin(runtimeName, relativePath, helperName) {
-  function adjustImportPath(node, relativePath) {
-    node.value =
-      helpers.list.indexOf(node.value) !== -1
-        ? `./${node.value}`
-        : node.value.replace(runtimeName + "/", relativePath + "/");
+function buildRuntimeRewritePlugin(runtimeName, helperName, esm) {
+  const helperPath = esm ? "helpers/esm" : "helpers";
+  /**
+   * rewrite helpers imports to runtime imports
+   * @example
+   * adjustImportPath(ast`"setPrototypeOf"`)
+   * // returns ast`"@babel/runtime/helpers/esm/setPrototypeOf"`
+   * @param {*} node The string literal contains import path
+   */
+  function adjustImportPath(node) {
+    if (helpers.list.includes(node.value)) {
+      node.value = `${runtimeName}/${helperPath}/${node.value}`;
+    }
   }
 
   return {
@@ -206,7 +245,7 @@ function buildRuntimeRewritePlugin(runtimeName, relativePath, helperName) {
     },
     visitor: {
       ImportDeclaration(path) {
-        adjustImportPath(path.get("source").node, relativePath);
+        adjustImportPath(path.get("source").node);
       },
       CallExpression(path) {
         if (
@@ -217,9 +256,8 @@ function buildRuntimeRewritePlugin(runtimeName, relativePath, helperName) {
           return;
         }
 
-        // replace any reference to @babel/runtime and other helpers
-        // with a relative path
-        adjustImportPath(path.get("arguments")[0].node, relativePath);
+        // replace reference to internal helpers with @babel/runtime import path
+        adjustImportPath(path.get("arguments")[0].node);
       },
     },
   };