feat(api/commit): add ls.dirs scope enumeration helper

Author: jrolfs

src/api/__tests__/__fixtures__/ls/dirs/.baz/.gitkeep

@@ -15,4 +15,22 @@ describe('ls', () => {
 
     expect(result.sort()).toEqual(expected.sort())
   })
+
+  describe('dirs', () => {
+    test('without prefix', () => {
+      const result = ls.dirs(`${fixtures}/ls/dirs`)
+
+      const expected = ['.baz', 'bar', 'foo']
+
+      expect(result.sort()).toEqual(expected.sort())
+    })
+
+    test('with prefix', () => {
+      const result = ls.dirs(`${fixtures}/ls/dirs`, 'prefix')
+
+      const expected = ['prefix/.baz', 'prefix/bar', 'prefix/foo']
+
+      expect(result.sort()).toEqual(expected.sort())
+    })
+  })
 })

src/api/__tests__/__fixtures__/ls/dirs/bar/.gitkeep

@@ -44,6 +44,18 @@ const configs = path =>
         )}`,
     )
 
-const ls = {configs}
+/**
+ * Enumerate one level of directories
+ *
+ * @param {string} path - directory to enumerate
+ * @param {string} [prefix] - prefix for each scope entry (e.g: `prefix/entry`)
+ */
+const dirs = (path, prefix) =>
+  readdirSync(path)
+    .filter(f => statSync(join(path, f)).isDirectory())
+    .map(item => (prefix ? `${prefix}/${item}` : item))
+    .map(item => item.toLowerCase())
+
+const ls = {configs, dirs}
 
 module.exports = {ls, scopes}