Minor refactors to parsing in preparation for bug fixes

Author: kristoferbaxter

src/parsing/export-details.ts

@@ -0,0 +1,65 @@
+/**
+ * Copyright 2020 The AMP HTML Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { ExportNamedDeclaration, ExportDefaultDeclaration } from 'estree';
+import { ExportDetails, Range, ExportClosureMapping } from '../types';
+
+export function NamedDeclaration(declaration: ExportNamedDeclaration): Array<ExportDetails> {
+  const range: Range = declaration.range as Range;
+  const source: string | null =
+    typeof declaration?.source?.value === 'string' ? declaration.source.value : null;
+
+  if (declaration.specifiers) {
+    const exportDetails: Array<ExportDetails> = [];
+
+    for (const specifier of declaration.specifiers) {
+      exportDetails.push({
+        local: specifier.local.name,
+        exported: specifier.exported.name,
+        closureName: specifier.exported.name,
+        type: ExportClosureMapping.NAMED_CONSTANT,
+        range,
+        source,
+      });
+    }
+
+    return exportDetails;
+  }
+
+  return [];
+}
+
+export function DefaultDeclaration(
+  defaultDeclaration: ExportDefaultDeclaration,
+): Array<ExportDetails> {
+  const range: Range = defaultDeclaration.range as Range;
+  const { declaration } = defaultDeclaration;
+
+  if (declaration.type === 'Identifier' && declaration.name) {
+    return [
+      {
+        local: declaration.name,
+        exported: declaration.name,
+        closureName: declaration.name,
+        type: ExportClosureMapping.NAMED_DEFAULT_FUNCTION,
+        range,
+        source: null,
+      },
+    ];
+  }
+
+  return [];
+}

src/parsing/literal-name.ts

@@ -0,0 +1,32 @@
+/**
+ * Copyright 2020 The AMP HTML Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { PluginContext } from 'rollup';
+import { Literal, SimpleLiteral } from 'estree';
+
+export function literalName(context: PluginContext, literal: Literal): string {
+  // Literal can either be a SimpleLiteral, or RegExpLiteral
+  if ('regex' in literal) {
+    // This is a RegExpLiteral
+    context.warn(
+      'Rollup Plugin Closure Compiler found a Regex Literal Named Import. `import foo from "*/.hbs"`',
+    );
+    return '';
+  }
+
+  const literalValue = (literal as SimpleLiteral).value;
+  return typeof literalValue === 'string' ? literalValue : '';
+}

src/transformers/exports.ts

@@ -22,7 +22,7 @@ import {
   Node,
 } from 'estree';
 import { TransformSourceDescription } from 'rollup';
-import { NamedDeclaration, DefaultDeclaration } from './parsing-utilities';
+import { NamedDeclaration, DefaultDeclaration } from '../parsing/export-details';
 import { isESMFormat } from '../options';
 import {
   Transform,
@@ -86,10 +86,10 @@ export default class ExportTransform extends Transform implements TransformInter
 
     walk.simple(program, {
       ExportNamedDeclaration(node: ExportNamedDeclaration) {
-        storeExport(NamedDeclaration(context, node));
+        storeExport(NamedDeclaration(node));
       },
       ExportDefaultDeclaration(node: ExportDefaultDeclaration) {
-        storeExport(DefaultDeclaration(context, node));
+        storeExport(DefaultDeclaration(node));
       },
       ExportAllDeclaration(node: ExportAllDeclaration) {
         // TODO(KB): This case `export * from "./import"` is not currently supported.

src/transformers/imports.ts

@@ -21,7 +21,7 @@ import {
   IMPORT_NAMESPACE_SPECIFIER,
   IMPORT_DEFAULT_SPECIFIER,
 } from '../types';
-import { literalName, importLocalNames } from './parsing-utilities';
+import { literalName } from '../parsing/literal-name';
 import { TransformSourceDescription } from 'rollup';
 import MagicString from 'magic-string';
 import { ImportDeclaration, Identifier, ImportSpecifier } from 'estree';
@@ -42,6 +42,19 @@ interface RangedImport {
   range: Range;
 }
 
+const VALID_SPECIFIERS = [IMPORT_SPECIFIER, IMPORT_NAMESPACE_SPECIFIER, IMPORT_DEFAULT_SPECIFIER];
+function importLocalNames(declaration: ImportDeclaration): Array<string> {
+  const returnableSpecifiers: Array<string> = [];
+
+  for (const specifier of declaration.specifiers || []) {
+    if (VALID_SPECIFIERS.includes(specifier.type)) {
+      returnableSpecifiers.push(specifier.local.name);
+    }
+  }
+
+  return returnableSpecifiers;
+}
+
 export default class ImportTransform extends Transform {
   private importedExternalsSyntax: { [key: string]: string } = {};
   private importedExternalsLocalNames: Array<string> = [];
@@ -117,7 +130,7 @@ window['${DYNAMIC_IMPORT_REPLACEMENT}'] = ${DYNAMIC_IMPORT_REPLACEMENT};`;
         source.remove(...range);
 
         self.importedExternalsLocalNames = self.importedExternalsLocalNames.concat(
-          importLocalNames(self.context, node),
+          importLocalNames(node),
         );
       },
       Import(node: RangedImport) {

src/transformers/parsing-utilities.ts

@@ -19,7 +19,7 @@ import { isESMFormat } from '../options';
 import { TransformSourceDescription } from 'rollup';
 import MagicString from 'magic-string';
 import { walk, parse } from '../acorn';
-import { ExpressionStatement } from 'estree';
+import { ExpressionStatement, SimpleLiteral } from 'estree';
 import { extname } from 'path';
 
 export default class StrictTransform extends Transform {
@@ -32,25 +32,17 @@ export default class StrictTransform extends Transform {
    * @return code after removing the strict mode declaration (when safe to do so)
    */
   public async postCompilation(code: string): Promise<TransformSourceDescription> {
-    if (this.outputOptions === null) {
-      this.context.warn(
-        'Rollup Plugin Closure Compiler, OutputOptions not known before Closure Compiler invocation.',
-      );
-    } else if (
-      isESMFormat(this.outputOptions.format) ||
-      (this.outputOptions.file && extname(this.outputOptions.file) === '.mjs')
-    ) {
+    const { format, file } = this.outputOptions;
+
+    if (isESMFormat(format) || (file && extname(file) === '.mjs')) {
       const source = new MagicString(code);
       const program = parse(code);
 
       walk.simple(program, {
         ExpressionStatement(node: ExpressionStatement) {
-          if (
-            node.expression.type === 'Literal' &&
-            node.expression.value === 'use strict' &&
-            node.range
-          ) {
-            source.remove(node.range[0], node.range[1]);
+          const { type, value } = node.expression as SimpleLiteral;
+          if (type === 'Literal' && value === 'use strict' && node.range) {
+            source.remove(...node.range);
           }
         },
       });

src/transformers/replacement-utilities.ts

@@ -69,7 +69,7 @@ export interface TransformInterface {
 export class Transform implements TransformInterface {
   protected context: PluginContext;
   protected inputOptions: InputOptions;
-  public outputOptions: OutputOptions | null;
+  public outputOptions: OutputOptions;
   public name: string = 'Transform';
 
   constructor(context: PluginContext, inputOptions: InputOptions) {
@@ -92,21 +92,4 @@ export class Transform implements TransformInterface {
       code,
     };
   }
-
-  // TODO (KB): Is this needed?
-  // protected isEntryPoint(id: string) {
-  //   const inputs = (input: InputOption): Array<string> => {
-  //     if (typeof input === 'string') {
-  //       return [input];
-  //     } else if (typeof input === 'object') {
-  //       return Object.values(input);
-  //     } else {
-  //       return input;
-  //     }
-  //   };
-
-  //   return inputs(this.inputOptions.input)
-  //     .map(input => path.resolve(input))
-  //     .includes(id);
-  // }
 }

src/transformers/strict.ts

@@ -7,7 +7,7 @@
     "outDir": "transpile",
     "sourceMap": true,
     "moduleResolution": "node",
-    "target": "esnext",
+    "target": "es2019",
     "baseUrl": ".",
     "allowJs": false,
     "noUnusedLocals": true,