vercel · jeremy-code · Jun 26, 2024 · Nov 12, 2024 · Nov 12, 2024 · Nov 12, 2024
@@ -1,6 +1,6 @@
 # `eslint-plugin-turbo`
 
-Ease configuration for Turborepo
+Easy ESLint configuration for Turborepo
 
 ## Installation
 
@@ -16,7 +16,7 @@ npm install eslint --save-dev
 npm install eslint-plugin-turbo --save-dev
 ```
 
-## Usage
+## Usage (Legacy `eslintrc*`)
 
 Add `turbo` to the plugins section of your `.eslintrc` configuration file. You can omit the `eslint-plugin-` prefix:
 
@@ -36,7 +36,7 @@ Then configure the rules you want to use under the rules section.
 }
 ```
 
-### Example
+## Example (Legacy `eslintrc*`)
 
 ```json
 {
@@ -51,3 +51,52 @@ Then configure the rules you want to use under the rules section.
   }
 }
 ```
+
+## Usage (Flat Config `eslint.config.js`)
+
+In ESLint v8, both the legacy system and the new flat config system are supported. In Eslint v9, only the new system will be supported. See the [official ESLint docs](https://eslint.org/docs/latest/use/configure/configuration-files).
+
+```js
+import turbo from "eslint-plugin-turbo";
+
+export default [turbo.configs["flat/recommended"]];
+```
+
+Otherwise, you may configure the rules you want to use under the rules section.
+
+```js
+import turbo from "eslint-plugin-turbo";
+
+export default [
+  {
+    plugins: {
+      turbo,
+    },
+    rules: {
+      "turbo/no-undeclared-env-vars": "error",
+    },
+  },
+];
+```
+
+## Example (Flat Config `eslint.config.js`)
+
+```js
+import turbo from "eslint-plugin-turbo";
+
+export default [
+  {
+    plugins: {
+      turbo,
+    },
+    rules: {
+      "turbo/no-undeclared-env-vars": [
+        "error",
+        {
+          allowList: ["^ENV_[A-Z]+$"],
+        },
+      ],
+    },
+  },
+];
+```
@@ -0,0 +1,3 @@
+const turbo = require("eslint-plugin-turbo");
+
+module.exports = [turbo.configs["flat/recommended"]];
@@ -1,10 +1,15 @@
 import path from "node:path";
 import { execSync } from "node:child_process";
+import JSON5, { parse, stringify } from "json5";
 import { type Schema } from "@turbo/types";
-import { parse, stringify } from "json5";
 import { setupTestFixtures } from "@turbo/test-utils";
 import { describe, it, expect } from "@jest/globals";
 
+const env: NodeJS.ProcessEnv = {
+  ...process.env,
+  ESLINT_USE_FLAT_CONFIG: "false",
+};
+
 describe("eslint settings check", () => {
   const { useFixture } = setupTestFixtures({
     directory: path.join(__dirname, "../"),
@@ -14,11 +19,15 @@ describe("eslint settings check", () => {
     const { root: cwd } = useFixture({ fixture: "workspace" });
     execSync(`npm install`, { cwd });
 
-    const configString = execSync(`npm exec eslint -- --print-config peer.js`, {
-      cwd,
-      encoding: "utf8",
-    });
-    const configJson: Record<string, unknown> = parse(configString);
+    const configString = execSync(
+      `npm exec eslint -- -c .eslintrc.js --print-config peer.js`,
+      {
+        cwd,
+        encoding: "utf8",
+        env,
+      }
+    );
+    const configJson = JSON5.parse(configString);
 
     expect(configJson.settings).toEqual({
       turbo: {
@@ -72,10 +81,11 @@ describe("eslint settings check", () => {
 
     const cwd = path.join(root, "child");
     const configString = execSync(
-      `npm exec eslint -- --print-config child.js`,
+      `npm exec eslint -- -c ../.eslintrc.js --print-config child.js`,
       {
         cwd,
         encoding: "utf8",
+        env,
       }
     );
     const configJson: Record<string, unknown> = parse(configString);
@@ -141,9 +151,10 @@ describe("eslint cache is busted", () => {
 
     const cwd = path.join(root, "child");
     try {
-      execSync(`npm exec eslint -- --format=json child.js`, {
+      execSync(`npm exec eslint -- -c ../.eslintrc.js --format=json child.js`, {
         cwd,
         encoding: "utf8",
+        env,
       });
     } catch (error: unknown) {
       const outputJson: Record<string, unknown> = parse(
@@ -169,11 +180,16 @@ describe("eslint cache is busted", () => {
     }
 
     // test that we invalidated the eslint cache
-    const output = execSync(`npm exec eslint -- --format=json child.js`, {
-      cwd,
-      encoding: "utf8",
-    });
-    const outputJson: Record<string, unknown> = parse(output);
+    const output = execSync(
+      `npm exec eslint -- -c ../.eslintrc.js --format=json child.js`,
+      {
+        cwd,
+        encoding: "utf8",
+        env,
+      }
+    );
+    const outputJson = JSON5.parse(output);
+
     expect(outputJson).toMatchObject([{ errorCount: 0 }]);
   });
 });
@@ -0,0 +1,194 @@
+import path from "path";
+import JSON5 from "json5";
+import { execSync } from "child_process";
+import { Schema } from "@turbo/types";
+import { setupTestFixtures } from "@turbo/test-utils";
+
+const env: NodeJS.ProcessEnv = {
+  ...process.env,
+  ESLINT_USE_FLAT_CONFIG: "true",
+};
+
+describe("flat eslint settings check", () => {
+  const { useFixture } = setupTestFixtures({
+    directory: path.join(__dirname, "../"),
+  });
+
+  it("does the right thing for peers", () => {
+    const { root: cwd } = useFixture({ fixture: "workspace" });
+    execSync(`npm install`, { cwd });
+
+    const configString = execSync(
+      `npm exec eslint -- -c eslint.config.js --print-config peer.js`,
+      {
+        cwd,
+        encoding: "utf8",
+        env,
+      }
+    );
+    const configJson = JSON5.parse(configString);
+
+    expect(configJson.settings).toEqual({
+      turbo: {
+        cacheKey: {
+          global: {
+            legacyConfig: [],
+            env: ["CI", "UNORDERED"],
+            passThroughEnv: null,
+            dotEnv: {
+              filePaths: [".env", "missing.env"],
+              hashes: {
+                ".env": "9ad6c5fd4d5bbe7c00e1f2b358ac7ef2aa3521d0",
+              },
+            },
+          },
+          globalTasks: {
+            build: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+            test: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+            lint: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+            deploy: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+          },
+          workspaceTasks: {},
+        },
+      },
+    });
+  });
+
+  it("does the right thing for child dirs", () => {
+    const { root } = useFixture({ fixture: "workspace" });
+    execSync(`npm install`, { cwd: root });
+
+    const cwd = path.join(root, "child");
+    const configString = execSync(
+      `npm exec eslint -- -c ../eslint.config.js --print-config child.js`,
+      {
+        cwd,
+        encoding: "utf8",
+        env,
+      }
+    );
+    const configJson = JSON5.parse(configString);
+
+    expect(configJson.settings).toEqual({
+      turbo: {
+        cacheKey: {
+          global: {
+            legacyConfig: [],
+            env: ["CI", "UNORDERED"],
+            passThroughEnv: null,
+            dotEnv: {
+              filePaths: [".env", "missing.env"],
+              hashes: {
+                ".env": "9ad6c5fd4d5bbe7c00e1f2b358ac7ef2aa3521d0",
+              },
+            },
+          },
+          globalTasks: {
+            build: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+            test: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+            lint: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+            deploy: {
+              legacyConfig: [],
+              env: [],
+              passThroughEnv: null,
+              dotEnv: null,
+            },
+          },
+          workspaceTasks: {},
+        },
+      },
+    });
+  });
+});
+
+describe("flat eslint cache is busted", () => {
+  const { useFixture } = setupTestFixtures({
+    directory: path.join(__dirname, "../"),
+  });
+
+  it("catches a lint error after changing config", () => {
+    expect.assertions(2);
+
+    // ensure that we populate the cache with a failure.
+    const { root, readJson, write } = useFixture({ fixture: "workspace" });
+    execSync(`npm install`, { cwd: root });
+
+    const cwd = path.join(root, "child");
+    try {
+      execSync(
+        `npm exec eslint -- -c ../eslint.config.js --format=json child.js`,
+        {
+          cwd,
+          encoding: "utf8",
+          env,
+        }
+      );
+    } catch (error: any) {
+      const outputJson = JSON5.parse(error.stdout);
+      expect(outputJson).toMatchObject([
+        {
+          messages: [
+            {
+              message:
+                "NONEXISTENT is not listed as a dependency in turbo.json",
+            },
+          ],
+        },
+      ]);
+    }
+
+    // change the configuration
+    const turboJson = readJson<Schema>("turbo.json");
+    if (turboJson && "globalEnv" in turboJson) {
+      turboJson.globalEnv = ["CI", "NONEXISTENT"];
+      write("turbo.json", JSON5.stringify(turboJson, null, 2));
+    }
+
+    // test that we invalidated the eslint cache
+    const output = execSync(
+      `npm exec eslint -- -c ../eslint.config.js --format=json child.js`,
+      {
+        cwd,
+        encoding: "utf8",
+        env,
+      }
+    );
+    const outputJson = JSON5.parse(output);
+    expect(outputJson).toMatchObject([{ errorCount: 0 }]);
+  });
+});
@@ -0,0 +1,19 @@
+import type { Linter } from "eslint";
+import { RULES } from "../../constants";
+import { Project } from "../../utils/calculate-inputs";
+
+const project = new Project(process.cwd());
+const cacheKey = project.valid() ? project.key() : Math.random();
+
+const config = {
+  rules: {
+    [`turbo/${RULES.noUndeclaredEnvVars}`]: "error",
+  },
+  settings: {
+    turbo: {
+      cacheKey,
+    },
+  },
+} satisfies Linter.FlatConfig;
+
+export default config;
@@ -1,3 +1,4 @@
+import type { Linter } from "eslint";
 import { RULES } from "../constants";
 import { Project } from "../utils/calculate-inputs";
 
@@ -16,6 +17,6 @@ const config = {
   rules: {
     [`turbo/${RULES.noUndeclaredEnvVars}`]: "error",
   },
-};
+} satisfies Linter.Config;
 
 export default config;
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		const turbo = require("eslint-plugin-turbo");

		module.exports = [turbo.configs["flat/recommended"]];