Breaking: Implement parseForESLint() function (#412)

Author: JamesHenry

README.md

@@ -1,6 +1,6 @@
-# TypeScript ESLint Parser (Experimental)
+# TypeScript ESLint Parser
 
-A parser that converts TypeScript into an [ESTree](https://github.com/estree/estree)-compatible form so it can be used in ESLint.
+A parser that converts TypeScript source code into an [ESTree](https://github.com/estree/estree)-compatible form.
 
 **Important:** This parser is not fully compatible with all ESLint rules and plugins. Some rules will improperly mark source code as failing or not find problems where it should.
 
@@ -20,18 +20,10 @@ The following ESLint rules will fail on acceptable code:
  - no-undef [#77](https://github.com/eslint/typescript-eslint-parser/issues/77)
  - no-unused-vars [#77](https://github.com/eslint/typescript-eslint-parser/issues/77)
  - no-useless-constructor [#77](https://github.com/eslint/typescript-eslint-parser/issues/77)
- - space-infix-ops [#224](https://github.com/eslint/typescript-eslint-parser/issues/224)
 
 The follow ESLint plugins have issues when used with this parser:
- - eslint-plugin-react [#213](https://github.com/eslint/typescript-eslint-parser/issues/213)
  - eslint-plugin-import
     - prefer-default-export - Will fail exports inside of Namespaces or Modules
-  
-The following TypeScript syntax will cause rules to fail or ESLint v3 to crash:
- - Empty body functions
-   - Abstract methods
-   - Function overloading
-   - Declared functions
 
 ## Usage
 

lib/ast-converter.js

@@ -58,7 +58,8 @@ module.exports = (ast, extra) => {
         ast,
         additionalOptions: {
             errorOnUnknownASTType: extra.errorOnUnknownASTType || false,
-            useJSXTextNode: extra.useJSXTextNode || false
+            useJSXTextNode: extra.useJSXTextNode || false,
+            parseForESLint: extra.parseForESLint
         }
     });
 

lib/convert.js

@@ -69,6 +69,21 @@ module.exports = function convert(config) {
         });
     }
 
+    /**
+     * If we are parsing for ESLint we need to perform a custom namespacing step
+     * on functions which have no body so that we do not break any ESLint rules which
+     * rely on them to have one.
+     *
+     * @param {ESTreeNode} functionNode the converted ESTreeNode
+     * @returns {void}
+     */
+    function namespaceEmptyBodyFunctionForESLint(functionNode) {
+        if (!config.additionalOptions.parseForESLint || functionNode.body) {
+            return;
+        }
+        functionNode.type = `TSEmptyBody${functionNode.type}`;
+    }
+
     /**
      * Converts a TypeScript node into an ESTree node.
      * @param  {TSNode} child the child TSNode
@@ -634,6 +649,8 @@ module.exports = function convert(config) {
                 result.typeParameters = convertTSTypeParametersToTypeParametersDeclaration(node.typeParameters);
             }
 
+            namespaceEmptyBodyFunctionForESLint(result);
+
             // check for exports
             result = nodeUtils.fixExports(node, result, ast);
 
@@ -954,6 +971,8 @@ module.exports = function convert(config) {
                 method.typeParameters = convertTSTypeParametersToTypeParametersDeclaration(node.typeParameters);
             }
 
+            namespaceEmptyBodyFunctionForESLint(result.value);
+
             break;
 
         }

package.json

@@ -21,7 +21,7 @@
     "babel-code-frame": "6.26.0",
     "babylon": "7.0.0-beta.34",
     "dedent": "0.7.0",
-    "eslint": "4.13.0",
+    "eslint": "4.13.1",
     "eslint-config-eslint": "4.0.0",
     "eslint-plugin-node": "5.2.1",
     "eslint-release": "0.10.3",

parser.js

@@ -1,6 +1,7 @@
 /**
  * @fileoverview Parser that converts TypeScript into ESTree format.
  * @author Nicholas C. Zakas
+ * @author James Henry <https://github.com/JamesHenry>
  * @copyright jQuery Foundation and other contributors, https://jquery.org/
  * MIT License
  */
@@ -45,11 +46,13 @@ function resetExtra() {
 
 /**
  * Parses the given source code to produce a valid AST
- * @param  {mixed} code    TypeScript code
- * @param  {Object} options configuration object for the parser
+ * @param {mixed} code    TypeScript code
+ * @param {Object} options configuration object for the parser
+ * @param {Object} additionalParsingContext additional internal configuration
  * @returns {Object}         the AST
  */
-function parse(code, options) {
+function generateAST(code, options, additionalParsingContext) {
+    additionalParsingContext = additionalParsingContext || {};
 
     const toString = String;
 
@@ -104,6 +107,13 @@ function parse(code, options) {
             extra.log = Function.prototype;
         }
 
+        /**
+         * Provide the context as to whether or not we are parsing for ESLint,
+         * specifically
+         */
+        if (additionalParsingContext.isParseForESLint) {
+            extra.parseForESLint = true;
+        }
     }
 
     if (!isRunningSupportedTypeScriptVersion && !warnedAboutTSVersion) {
@@ -175,7 +185,14 @@ function parse(code, options) {
 
 exports.version = require("./package.json").version;
 
-exports.parse = parse;
+exports.parse = function parse(code, options) {
+    return generateAST(code, options, { isParseForESLint: false });
+};
+
+exports.parseForESLint = function parseForESLint(code, options) {
+    const ast = generateAST(code, options, { isParseForESLint: true });
+    return { ast };
+};
 
 // Deep copy.
 /* istanbul ignore next */

tests/integration/external-fixtures/declared-empty-body-functions.js

@@ -0,0 +1,21 @@
+"use strict";
+
+declare namespace FF {
+    class Foo extends Bar.Baz {
+        far(): any;
+    }
+}
+
+declare module "FF" {
+    class Foo extends Bar.Baz {
+        far(): any;
+    }
+}
+
+declare class Foo extends Bar.Baz {
+    far(): any;
+}
+
+declare namespace d3 {
+    export function select(selector: string): Selection<any>;
+}

tests/integration/external-fixtures/jsdoc-indent.js

@@ -0,0 +1,12 @@
+/**
+ * @a
+ */
+foo;
+
+/**
+ * @a
+ */
+/**
+ * a
+ */
+foo;

tests/integration/external-fixtures/no-redeclare-overloaded-functions.js

@@ -0,0 +1,14 @@
+export async function readFile(
+  filename: string,
+  options?: { flag?: string }
+): Promise<Buffer>
+export async function readFile(
+  filename: string,
+  options?: { encoding: BufferEncoding; flag?: string }
+): Promise<string>
+export async function readFile(
+  filename: string,
+  options?: { encoding?: string; flag?: string }
+): Promise<Buffer | string> {
+  // ...
+}

tests/integration/external-fixtures/range-error-indent.js

@@ -0,0 +1,4 @@
+class a {
+    /** @b {} c */
+    d = e => {}
+}