Add supports for importing a folder with trailing slash on the path (#…

…529)

* Avoid duplicated trailing slash on the folder path

* Add a test case for trailing slash on a path of folder

* Add an usage of import relative path in directory index file

src/commands/import-resolver.ts

@@ -29,7 +29,8 @@ export function getImportStats(dirLoc: string, spec: string): Stats | false {
 /** Resolve an import based on the state of the file/folder found on disk. */
 function resolveSourceSpecifier(spec: string, stats: Stats | false, isBundled: boolean) {
   if (stats && stats.isDirectory()) {
-    spec = spec + '/index.js';
+    const trailingSlash = spec.endsWith('/') ? '' : '/';
+    spec = spec + trailingSlash + 'index.js';
   } else if (!stats && !spec.endsWith('.js')) {
     spec = spec + '.js';
   }

test/build/resolve-imports/expected-build/_dist_/components/index.js

@@ -1 +1,4 @@
+import sort2 from "../sort.js";
+console.log(sort2);
+
 export default "Button";

test/build/resolve-imports/expected-build/_dist_/index.js

@@ -5,12 +5,13 @@ import sort_ from "/_dist_/sort.js";
 import sort__ from "/_dist_/sort.js";
 console.log(sort2, sort_, sort__);
 import components2 from "./components/index.js";
+import components______ from "./components/index.js";
 import components_ from "./components/index.js";
 import components__ from "./components/index.js";
 import components___ from "/_dist_/components/index.js";
 import components____ from "/_dist_/components/index.js";
 import components_____ from "/_dist_/components/index.js";
-console.log(components2, components_, components__, components___, components____, components_____);
+console.log(components2, components_, components__, components___, components____, components_____, components______);
 import styles from "./components/style.css.proxy.js";
 import styles_ from "/_dist_/components/style.css.proxy.js";
 console.log(styles, styles_);

test/build/resolve-imports/src/components/index.js

@@ -1 +1,4 @@
-export default 'Button';
+import sort from '../sort';
+console.log(sort);
+
+export default 'Button';

test/build/resolve-imports/src/index.js

@@ -10,15 +10,16 @@ console.log(sort, sort_, sort__);
 
 // Importing a directory index.js file
 import components from './components'; // relative import 
+import components______ from './components/'; // relative import with trailing slash
 import components_ from './components/index'; // relative import with index appended
 import components__ from './components/index.js'; // relative import with index appended
 import components___ from 'src/components'; // bare import using mount
 import components____ from 'src/components/index'; // bare import using mount and index appended
 import components_____ from 'src/components/index.js'; // bare import using mount and index.js appended
-console.log(components, components_, components__, components___, components____, components_____);
+console.log(components, components_, components__, components___, components____, components_____, components______);
 
 
 // Importing something that isn't JS
 import styles from './components/style.css'; // relative import 
 import styles_ from 'src/components/style.css'; // relative import 
-console.log(styles, styles_);
+console.log(styles, styles_);