handle case when extends is single string, add some tests

gatsbyjs · LekoArts · Jan 13, 2021 · Jan 7, 2021 · Jan 11, 2021 · Jan 11, 2021
commit f5ad45a070346ccc8e380180c31b6b71a9ef02ac
diff --git a/packages/gatsby/src/utils/__tests__/eslint-config.ts b/packages/gatsby/src/utils/__tests__/eslint-config.ts
@@ -0,0 +1,130 @@
+import { mergeRequiredConfigIn } from "../eslint-config"
+import { CLIEngine } from "eslint"
+import * as path from "path"
+
+describe(`eslint-config`, () => {
+  describe(`mergeRequiredConfigIn`, () => {
+    it(`adds rulePaths and extends if those don't exist`, () => {
+      const conf: CLIEngine.Options = {}
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf?.baseConfig).toMatchInlineSnapshot(`
+        Object {
+          "extends": Array [
+            "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint/required.js",
+          ],
+        }
+      `)
+
+      expect(conf.rulePaths).toMatchInlineSnapshot(`
+        Array [
+          "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint-rules",
+        ]
+      `)
+    })
+
+    it(`adds rulePath if rulePaths exist but don't contain required rules`, () => {
+      const conf: CLIEngine.Options = {
+        rulePaths: [`test`],
+      }
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf.rulePaths).toMatchInlineSnapshot(`
+        Array [
+          "test",
+          "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint-rules",
+        ]
+      `)
+    })
+
+    it(`doesn't add rulePath multiple times`, () => {
+      const conf: CLIEngine.Options = {
+        rulePaths: [path.resolve(__dirname, `../eslint-rules`), `test`],
+      }
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf.rulePaths).toMatchInlineSnapshot(`
+        Array [
+          "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint-rules",
+          "test",
+        ]
+      `)
+    })
+
+    it(`adds extend if extends exist (array) but don't contain required preset`, () => {
+      const conf: CLIEngine.Options = {
+        baseConfig: {
+          extends: [`ext1`],
+        },
+      }
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf.baseConfig).toMatchInlineSnapshot(`
+        Object {
+          "extends": Array [
+            "ext1",
+            "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint/required.js",
+          ],
+        }
+      `)
+    })
+
+    it(`adds extend if extends exist (string) but don't contain required preset`, () => {
+      const conf: CLIEngine.Options = {
+        baseConfig: {
+          extends: `ext1`,
+        },
+      }
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf.baseConfig).toMatchInlineSnapshot(`
+        Object {
+          "extends": Array [
+            "ext1",
+            "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint/required.js",
+          ],
+        }
+      `)
+    })
+
+    it(`doesn't add extend multiple times (extends is array)`, () => {
+      const conf: CLIEngine.Options = {
+        baseConfig: {
+          extends: [require.resolve(`../eslint/required`), `ext1`],
+        },
+      }
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf.baseConfig).toMatchInlineSnapshot(`
+        Object {
+          "extends": Array [
+            "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint/required.js",
+            "ext1",
+          ],
+        }
+      `)
+    })
+
+    it(`doesn't add extend multiple times (extends is string)`, () => {
+      const conf: CLIEngine.Options = {
+        baseConfig: {
+          extends: require.resolve(`../eslint/required`),
+        },
+      }
+
+      mergeRequiredConfigIn(conf)
+
+      expect(conf.baseConfig).toMatchInlineSnapshot(`
+        Object {
+          "extends": "<PROJECT_ROOT>/packages/gatsby/src/utils/eslint/required.js",
+        }
+      `)
+    })
+  })
+})
diff --git a/packages/gatsby/src/utils/eslint-config.ts b/packages/gatsby/src/utils/eslint-config.ts
@@ -42,6 +42,14 @@ export function mergeRequiredConfigIn(
       !existingOptions.baseConfig.extends.includes(eslintRequirePreset)
     ) {
       existingOptions.baseConfig.extends.push(eslintRequirePreset)
+    } else if (
+      typeof existingOptions.baseConfig.extends === `string` &&
+      existingOptions.baseConfig.extends !== eslintRequirePreset
+    ) {
+      existingOptions.baseConfig.extends = [
+        existingOptions.baseConfig.extends,
+        eslintRequirePreset,
+      ]
     }
   } else {
     existingOptions.baseConfig.extends = [eslintRequirePreset]