fix(source-maps): map nameless nodes

src/astring.js

@@ -1052,16 +1052,18 @@ class State {
         this.line++
         return
       }
+      if (node.loc != null) {
+        const { mapping } = this
+        mapping.original = node.loc.start
+        mapping.name = node.name
+        this.sourceMap.addMapping(mapping)
+      }
       if (
         (type[0] === 'T' && type[8] === 'E') ||
         (type[0] === 'L' && type[1] === 'i' && typeof node.value === 'string')
       ) {
         // TemplateElement or Literal string node
         const { length } = code
-        if (length === 0 || (length === 2 && type[0] === 'L')) {
-          // Empty TemplateElement or Literal string with begin and end quotes
-          return
-        }
         let { column, line } = this
         for (let i = 0; i < length; i++) {
           if (code[i] === '\n') {
@@ -1075,12 +1077,6 @@ class State {
         this.line = line
         return
       }
-      if (node.name != null) {
-        const { mapping } = this
-        mapping.original = node.loc.start
-        mapping.name = node.name
-        this.sourceMap.addMapping(mapping)
-      }
     }
     const { length } = code
     const { lineEnd } = this

src/tests/astring.js

@@ -134,12 +134,12 @@ test('Source map generation', (assert) => {
     const code = readFile(path.join(dirname, filename))
     const sourceMap = {
       mappings: [],
-      _file: 'script.js',
+      _file: filename,
       addMapping({ original, generated, name, source }) {
         assert.deepEqual(
           pick(generated, ['line', 'column']),
           pick(original, ['line', 'column']),
-          `${filename}:${name}`,
+          `${source}:${name}`,
         )
         assert.is(source, this._file)
         this.mappings.push({
@@ -156,3 +156,41 @@ test('Source map generation', (assert) => {
     })
   })
 })
+
+test('Source map generation with comments', (assert) => {
+  const dirname = path.join(FIXTURES_FOLDER, 'comment')
+  const files = fs.readdirSync(dirname).sort()
+  files.forEach((filename) => {
+    const code = readFile(path.join(dirname, filename))
+    const sourceMap = {
+      mappings: [],
+      _file: filename,
+      addMapping({ original, generated, name, source }) {
+        assert.deepEqual(
+          pick(generated, ['line', 'column']),
+          pick(original, ['line', 'column']),
+          `${source}:${name}`,
+        )
+        assert.is(source, this._file)
+        this.mappings.push({
+          original,
+          generated,
+          name,
+          source,
+        })
+      },
+    }
+    const comments = []
+    const ast = parse(code, {
+      ecmaVersion,
+      comments: true,
+      locations: true,
+      onComment: comments,
+    })
+    astravel.attachComments(ast, comments)
+    generate(ast, {
+      sourceMap,
+      comments: true,
+    })
+  })
+})