build(package): support subpath alias with top-level root

.gitignore

@@ -19,10 +19,18 @@ img/
 spec-js/
 spec-build/
 .out/
+.tmp/
+
+ajax/
+fetch/
+operators/
+testing/
+webSocket/
 
 # Misc
 npm-debug.log
 .DS_STORE
+*.tgz
 
 # The check-side-effects package generates and deletes this file.
 # If the process is killed, it will be left behind.

tools/generate-alias.js

@@ -0,0 +1,28 @@
+/**
+ * Alias subpath import (`dist/cjs/*`) to top-level path mapping (`rxjs/*`)
+ * Previously this was done by placing cjs to top-level package when it's published -
+ * Now build uses `dist` as explicit output subpath so we generate top-level alias here instead.
+ */
+const fs = require('fs-extra');
+const path = require('path');
+
+const aliasRoot = [
+  'ajax', 'fetch', 'operators', 'testing', 'webSocket'
+]
+
+aliasRoot.forEach((alias) => fs.removeSync(alias));
+aliasRoot.forEach((alias) => fs.ensureDirSync(alias));
+
+aliasRoot.forEach((alias) => {
+  const pkgManifest = {
+    "name": `rxjs/${alias}`,
+    "typings": `../dist/types/${alias}/index.d.ts`,
+    "main": `../dist/cjs/${alias}/index.js`,
+    "module": `../dist/esm5/${alias}/index.js`,
+    "es2015": `../dist/esm/${alias}/index.js`,
+    "sideEffects": false
+  };
+
+  fs.writeJSON(path.resolve(__dirname, `../${alias}/package.json`), pkgManifest, { spaces: 2 });
+});
+