Add react-x/jsx-dollar rule, closes #1300

apps/website/content/docs/rules/meta.json

@@ -2,6 +2,7 @@
   "pages": [
     "overview",
     "---X Rules---",
+    "jsx-dollar",
     "jsx-key-before-spread",
     "jsx-no-comment-textnodes",
     "jsx-no-duplicate-props",

apps/website/content/docs/rules/overview.mdx

@@ -27,6 +27,7 @@ full: true
 
 | Rule                                                                                 |    ✅    |     🌟    | Description                                                                                         |  `react` |
 | :----------------------------------------------------------------------------------- | :-----: | :-------: | :-------------------------------------------------------------------------------------------------- | :------: |
+| [`jsx-dollar`](./jsx-dollar)                                                         | 0️⃣ 0️⃣ |           | Prevents unnecessary dollar signs (`$`) from being inserted before an expression in JSX             |          |
 | [`jsx-key-before-spread`](./jsx-key-before-spread)                                   | 1️⃣ 1️⃣ |           | Enforces that the 'key' prop is placed before the spread prop in JSX elements                       |          |
 | [`jsx-no-comment-textnodes`](./jsx-no-comment-textnodes)                             | 1️⃣ 1️⃣ |           | Prevents comments from being inserted as text nodes                                                 |          |
 | [`jsx-no-duplicate-props`](./jsx-no-duplicate-props)                                 | 1️⃣ 1️⃣ |           | Disallow duplicate props in JSX elements                                                            |          |

dprint.json

@@ -25,7 +25,7 @@
     "packages/**/docs"
   ],
   "plugins": [
-    "https://plugins.dprint.dev/typescript-0.95.11.wasm",
+    "https://plugins.dprint.dev/typescript-0.95.12.wasm",
     "https://plugins.dprint.dev/json-0.21.0.wasm",
     "https://plugins.dprint.dev/markdown-0.20.0.wasm",
     "https://plugins.dprint.dev/toml-0.7.0.wasm",

packages/plugins/eslint-plugin-react-x/src/plugin.ts

@@ -2,6 +2,7 @@ import type { CompatiblePlugin } from "@eslint-react/shared";
 
 import { name, version } from "../package.json";
 
+import jsxDollar from "./rules/jsx-dollar";
 import jsxKeyBeforeSpread from "./rules/jsx-key-before-spread";
 import jsxNoCommentTextnodes from "./rules/jsx-no-comment-textnodes";
 import jsxNoDuplicateProps from "./rules/jsx-no-duplicate-props";
@@ -71,6 +72,7 @@ export const plugin: CompatiblePlugin = {
     version,
   },
   rules: {
+    "jsx-dollar": jsxDollar,
     "jsx-key-before-spread": jsxKeyBeforeSpread,
     "jsx-no-comment-textnodes": jsxNoCommentTextnodes,
     "jsx-no-duplicate-props": jsxNoDuplicateProps,

packages/plugins/eslint-plugin-react-x/src/rules/jsx-dollar.mdx

@@ -0,0 +1,101 @@
+---
+title: jsx-dollar
+---
+
+**Full Name in `@eslint-react/eslint-plugin`**
+
+```plain copy
+@eslint-react/jsx-dollar
+```
+
+**Full Name in `eslint-plugin-react-x`**
+
+```plain copy
+react-x/jsx-dollar
+```
+
+**Features**
+
+`🔧`
+
+## Description
+
+Prevents unnecessary dollar signs (`$`) from being inserted before an expression in JSX.
+
+This can happen when refactoring from a template literal to JSX and forgetting to remove the dollar sign. This results in an unintentional `$` being rendered in the output.
+
+```tsx
+import React from "react";
+
+function MyComponent({ user }) {
+  return `Hello ${user.name}`;
+}
+```
+
+When refactored to JSX, it might look like this:
+
+```tsx
+import React from "react";
+
+function MyComponent({ user }) {
+  return <>Hello ${user.name}</>;
+}
+```
+
+In this example, the `$` before `{user.name}` is unnecessary and will be rendered as part of the output.
+
+## Examples
+
+### Failing
+
+```tsx
+import React from "react";
+
+function MyComponent({ user }) {
+  return <div>Hello ${user.name}</div>;
+  //          ^^^^^^^
+  //          - Possible unnecessary '$' character before expression.
+}
+```
+
+```tsx
+import React from "react";
+
+function MyComponent({ user }) {
+  return <div>${user.name} is your name</div>;
+  //          ^
+  //          - Possible unnecessary '$' character before expression.
+}
+```
+
+### Passing
+
+```tsx
+import React from "react";
+
+function MyComponent({ user }) {
+  return `Hello ${user.name}`;
+}
+```
+
+```tsx
+import React from "react";
+
+function MyComponent({ user }) {
+  return <div>Hello {user.name}</div>;
+}
+```
+
+```tsx
+import React from "react";
+
+function MyComponent({ price }) {
+  // 🟢 Good: If there are only two children (the dollar sign and the expression) it doesn't seem to be split from a template literal
+  return <div>${price}</div>;
+}
+```
+
+## Implementation
+
+- [Rule Source](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x/src/rules/jsx-dollar.ts)
+- [Test Source](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x/src/rules/jsx-dollar.spec.ts)

packages/plugins/eslint-plugin-react-x/src/rules/jsx-dollar.spec.ts

@@ -0,0 +1,129 @@
+import tsx from "dedent";
+
+import { allValid, ruleTester } from "../../../../../test";
+import rule, { RULE_NAME } from "./jsx-dollar";
+
+ruleTester.run(RULE_NAME, rule, {
+  invalid: [
+    {
+      code: tsx`
+        const MyComponent = () => <>Hello \${user.name}</>
+      `,
+      errors: [
+        {
+          messageId: "jsxDollar",
+          suggestions: [
+            {
+              messageId: "removeDollarSign",
+              output: tsx`
+                const MyComponent = () => <>Hello {user.name}</>
+              `,
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: tsx`
+        const App = (props) => {
+            return <div>Hello \${props.name}</div>;
+        };
+      `,
+      errors: [
+        {
+          messageId: "jsxDollar",
+          suggestions: [
+            {
+              messageId: "removeDollarSign",
+              output: tsx`
+                const App = (props) => {
+                    return <div>Hello {props.name}</div>;
+                };
+              `,
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: tsx`
+        const App = (props) => {
+            return <div>\${props.name} is your name</div>;
+        };
+      `,
+      errors: [
+        {
+          messageId: "jsxDollar",
+          suggestions: [
+            {
+              messageId: "removeDollarSign",
+              output: tsx`
+                const App = (props) => {
+                    return <div>{props.name} is your name</div>;
+                };
+              `,
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: tsx`
+        const App = (props) => {
+            return <div>Hello \${props.name} is your name</div>;
+        };
+      `,
+      errors: [
+        {
+          messageId: "jsxDollar",
+          suggestions: [
+            {
+              messageId: "removeDollarSign",
+              output: tsx`
+                const App = (props) => {
+                    return <div>Hello {props.name} is your name</div>;
+                };
+              `,
+            },
+          ],
+        },
+      ],
+    },
+  ],
+  valid: [
+    ...allValid,
+    tsx`
+      const MyComponent = () => \`Hello \${user.name}\`
+    `,
+    tsx`
+      const App = (props) => {
+          return [<div key="1">1</div>]
+      };
+    `,
+    tsx`
+      const App = (props) => {
+          return <div>Hello $</div>;
+      };
+    `,
+    tsx`
+      const App = (props) => {
+          return <div>Hello {props.name}</div>;
+      };
+    `,
+    tsx`
+      import React from "react";
+
+      function MyComponent({ price }) {
+        // 🟢 Good: This is a legitimate use of the '$' character.
+        return <div>{\`$\${price}\`}</div>;
+      }
+    `,
+    tsx`
+      import React from "react";
+      function AnotherComponent({ price }) {
+        // 🟢 Good: Another legitimate way to display a price.
+        return <div>\${price}</div>;
+      }
+    `,
+  ],
+});

packages/plugins/eslint-plugin-react-x/src/rules/jsx-dollar.ts

@@ -0,0 +1,67 @@
+import type { RuleContext, RuleFeature } from "@eslint-react/shared";
+import type { TSESTree } from "@typescript-eslint/types";
+import { AST_NODE_TYPES as T } from "@typescript-eslint/types";
+import type { RuleListener } from "@typescript-eslint/utils/ts-eslint";
+import type { CamelCase } from "string-ts";
+
+import { createRule } from "../utils";
+
+export const RULE_NAME = "jsx-dollar";
+
+export const RULE_FEATURES = [] as const satisfies RuleFeature[];
+
+export type MessageID = CamelCase<typeof RULE_NAME> | RuleSuggestMessageID;
+
+export type RuleSuggestMessageID = "removeDollarSign";
+
+export default createRule<[], MessageID>({
+  meta: {
+    type: "problem",
+    docs: {
+      description: "Prevents dollar signs from being inserted as text nodes before expressions.",
+      [Symbol.for("rule_features")]: RULE_FEATURES,
+    },
+    fixable: "code",
+    hasSuggestions: true,
+    messages: {
+      jsxDollar: "Possible unnecessary '$' character before expression.",
+      removeDollarSign: "Remove the dollar sign '$' before the expression.",
+    },
+    schema: [],
+  },
+  name: RULE_NAME,
+  create,
+  defaultOptions: [],
+});
+
+export function create(context: RuleContext<MessageID, []>): RuleListener {
+  /**
+   * Visitor function for JSXElement and JSXFragment nodes
+   * @param node The JSXElement or JSXFragment node to be checked
+   */
+  const visitorFunction = (node: TSESTree.JSXElement | TSESTree.JSXFragment) => {
+    for (const [index, child] of node.children.entries()) {
+      if (child.type !== T.JSXText || !child.value.endsWith("$")) continue;
+      // Ensure the next sibling is a JSXExpressionContainer
+      if (node.children[index + 1]?.type !== T.JSXExpressionContainer) continue;
+      // Skip if there are only two children (the dollar sign and the expression) it doesn't seem to be split from a template literal
+      if (child.value === "$" && node.children.length === 2) continue;
+      context.report({
+        messageId: "jsxDollar",
+        node: child,
+        suggest: [
+          {
+            messageId: "removeDollarSign",
+            fix(fixer) {
+              return fixer.removeRange([child.range[1] - 1, child.range[1]]);
+            },
+          },
+        ],
+      });
+    }
+  };
+  return {
+    JSXElement: visitorFunction,
+    JSXFragment: visitorFunction,
+  };
+}

packages/plugins/eslint-plugin/README.md

@@ -186,8 +186,8 @@ ESLint React is not affiliated with Meta Corporation or [facebook/react](https:/
 
 Contributions are welcome!
 
-Please follow our [contributing guidelines](https://github.com/Rel1cx/eslint-react/tree/main/.github/CONTRIBUTING.md).
+Please follow our [contributing guidelines](https://github.com/Rel1cx/eslint-react/tree/jsx-dollar/.github/CONTRIBUTING.md).
 
 ## License
 
-This project is licensed under the MIT License - see the [LICENSE](https://github.com/Rel1cx/eslint-react/tree/main/LICENSE) file for details.
+This project is licensed under the MIT License - see the [LICENSE](https://github.com/Rel1cx/eslint-react/tree/jsx-dollar/LICENSE) file for details.