Breaking: switch 'jsx' option by filename (fixes #517) (#543)

* Breaking: switch 'jsx' option by filename (fixes #517)

* update README.md

* don't modify the option object

* update behavior

* use expect() instead of assert()

Author: mysticatea

README.md

@@ -36,9 +36,12 @@ By far the most common case will be installing the [eslint-plugin-typescript](ht
 
 The following additional configuration options are available by specifying them in [`parserOptions`](https://eslint.org/docs/user-guide/configuring#specifying-parser-options) in your ESLint configuration file.
 
-**`jsx`** - default `false`. Enable parsing JSX when `true`. More details can be found [here](https://www.typescriptlang.org/docs/handbook/jsx.html).
+- **`jsx`** - default `false`. Enable parsing JSX when `true`. More details can be found [here](https://www.typescriptlang.org/docs/handbook/jsx.html).
+    - It's `false` on `*.ts` files regardless of this option.
+    - It's `true` on `*.tsx` files regardless of this option.
+    - Otherwise, it respects this option.
 
-**`useJSXTextNode`** - default `false`. The JSX AST changed the node type for string literals inside a JSX Element from `Literal` to `JSXText`. When value is `true`, these nodes will be parsed as type `JSXText`. When value is `false`, these nodes will be parsed as type `Literal`.
+- **`useJSXTextNode`** - default `false`. The JSX AST changed the node type for string literals inside a JSX Element from `Literal` to `JSXText`. When value is `true`, these nodes will be parsed as type `JSXText`. When value is `false`, these nodes will be parsed as type `Literal`.
 
 ### .eslintrc.json
 

parser.js

@@ -20,6 +20,13 @@ const visitorKeys = require("./visitor-keys");
 exports.version = require("./package.json").version;
 
 exports.parseForESLint = function parseForESLint(code, options) {
+    if (options && typeof options.filePath === "string") {
+        const tsx = options.filePath.endsWith(".tsx");
+        if (tsx || options.filePath.endsWith(".ts")) {
+            options = Object.assign({}, options, { jsx: tsx });
+        }
+    }
+
     const ast = parse(code, options);
     traverser.traverse(ast, {
         enter: node => {

tests/lib/tsx.js

@@ -11,8 +11,11 @@
 // Requirements
 //------------------------------------------------------------------------------
 
-const path = require("path"),
+const
+    path = require("path"),
+    { Linter } = require("eslint"),
     shelljs = require("shelljs"),
+    parser = require("../../"),
     testUtils = require("../../tools/test-utils");
 
 //------------------------------------------------------------------------------
@@ -39,4 +42,102 @@ describe("TSX", () => {
         };
         test(`fixtures/${filename}.src`, testUtils.createSnapshotTestBlock(code, config));
     });
+
+    describe("if the filename ends with '.tsx', enable jsx option automatically.", () => {
+        const linter = new Linter();
+        linter.defineParser("typescript-eslint-parser", parser);
+
+        test("filePath was not provided", () => {
+            const code = "const element = <T/>";
+            const config = {
+                parser: "typescript-eslint-parser"
+            };
+            const messages = linter.verify(code, config);
+
+            expect(messages).toStrictEqual([{
+                column: 18,
+                fatal: true,
+                line: 1,
+                message: "Parsing error: '>' expected.",
+                ruleId: null,
+                severity: 2,
+                source: "const element = <T/>"
+            }]);
+        });
+
+        test("filePath was not provided and 'jsx:true' option", () => {
+            const code = "const element = <T/>";
+            const config = {
+                parser: "typescript-eslint-parser",
+                parserOptions: {
+                    jsx: true
+                }
+            };
+            const messages = linter.verify(code, config);
+
+            expect(messages).toStrictEqual([]);
+        });
+
+        test("test.ts", () => {
+            const code = "const element = <T/>";
+            const config = {
+                parser: "typescript-eslint-parser"
+            };
+            const messages = linter.verify(code, config, { filename: "test.ts" });
+
+            expect(messages).toStrictEqual([{
+                column: 18,
+                fatal: true,
+                line: 1,
+                message: "Parsing error: '>' expected.",
+                ruleId: null,
+                severity: 2,
+                source: "const element = <T/>"
+            }]);
+        });
+
+        test("test.ts with 'jsx:true' option", () => {
+            const code = "const element = <T/>";
+            const config = {
+                parser: "typescript-eslint-parser",
+                parserOptions: {
+                    jsx: true
+                }
+            };
+            const messages = linter.verify(code, config, { filename: "test.ts" });
+
+            expect(messages).toStrictEqual([{
+                column: 18,
+                fatal: true,
+                line: 1,
+                message: "Parsing error: '>' expected.",
+                ruleId: null,
+                severity: 2,
+                source: "const element = <T/>"
+            }]);
+        });
+
+        test("test.tsx", () => {
+            const code = "const element = <T/>";
+            const config = {
+                parser: "typescript-eslint-parser"
+            };
+            const messages = linter.verify(code, config, { filename: "test.tsx" });
+
+            expect(messages).toStrictEqual([]);
+        });
+
+        test("test.tsx with 'jsx:false' option", () => {
+            const code = "const element = <T/>";
+            const config = {
+                parser: "typescript-eslint-parser",
+                parserOptions: {
+                    jsx: false
+                }
+            };
+            const messages = linter.verify(code, config, { filename: "test.tsx" });
+
+            expect(messages).toStrictEqual([]);
+        });
+    });
 });