feat(require-author): add new require-author rule

README.md

@@ -126,6 +126,7 @@ The default settings don't conflict, and Prettier plugins can quickly fix up ord
 | [no-redundant-files](docs/rules/no-redundant-files.md)                 | Prevents adding unnecessary / redundant files.                                                    |    |    | 💡 |    |
 | [order-properties](docs/rules/order-properties.md)                     | Package properties must be declared in standard order                                             | ✅  | 🔧 |    |    |
 | [repository-shorthand](docs/rules/repository-shorthand.md)             | Enforce either object or shorthand declaration for repository.                                    | ✅  | 🔧 |    |    |
+| [require-author](docs/rules/require-author.md)                         | Requires the `author` property to be present.                                                     |    |    |    |    |
 | [sort-collections](docs/rules/sort-collections.md)                     | Dependencies, scripts, and configuration values must be declared in alphabetical order.           | ✅  | 🔧 |    |    |
 | [unique-dependencies](docs/rules/unique-dependencies.md)               | Checks a dependency isn't specified more than once (i.e. in `dependencies` and `devDependencies`) | ✅  |    | 💡 |    |
 | [valid-local-dependency](docs/rules/valid-local-dependency.md)         | Checks existence of local dependencies in the package.json                                        | ✅  |    |    |    |

docs/rules/require-author.md

@@ -0,0 +1,25 @@
+# require-author
+
+<!-- end auto-generated rule header -->
+
+This rule checks for the existence of the `"author"` property in a package.json,
+and reports a violation if it doesn't exist.
+
+Example of **incorrect** code for this rule:
+
+```json
+{
+	"name": "thee-silver-mt-zion",
+	"version": "13.0.0"
+}
+```
+
+Example of **correct** code for this rule:
+
+```json
+{
+	"name": "thee-silver-mt-zion",
+	"version": "13.0.0",
+	"author": "Jessica Moss"
+}
+```

package.json

@@ -39,7 +39,7 @@
 		"build": "tsup",
 		"format": "prettier \"**/*\" --ignore-unknown",
 		"lint": "eslint . --max-warnings 0",
-		"lint:eslint-docs": "npm run update:eslint-docs -- --check",
+		"lint:eslint-docs": "pnpm update:eslint-docs --check",
 		"lint:knip": "knip",
 		"lint:md": "markdownlint \"**/*.md\" \".github/**/*.md\"",
 		"lint:packages": "pnpm dedupe --check",

src/plugin.ts

@@ -6,6 +6,7 @@ import { rule as noEmptyFields } from "./rules/no-empty-fields.js";
 import { rule as noRedundantFiles } from "./rules/no-redundant-files.js";
 import { rule as orderProperties } from "./rules/order-properties.js";
 import { rule as preferRepositoryShorthand } from "./rules/repository-shorthand.js";
+import { rules as requireRules } from "./rules/require-properties.js";
 import { rule as sortCollections } from "./rules/sort-collections.js";
 import { rule as uniqueDependencies } from "./rules/unique-dependencies.js";
 import { rule as validLocalDependency } from "./rules/valid-local-dependency.js";
@@ -25,6 +26,7 @@ const rules: Record<string, PackageJsonRuleModule> = {
 	"no-empty-fields": noEmptyFields,
 	"no-redundant-files": noRedundantFiles,
 	"order-properties": orderProperties,
+	...requireRules,
 	"repository-shorthand": preferRepositoryShorthand,
 	"sort-collections": sortCollections,
 	"unique-dependencies": uniqueDependencies,

src/rules/require-properties.ts

@@ -0,0 +1,22 @@
+import type { PackageJsonRuleModule } from "../createRule.js";
+
+import { createRequirePropertyRule } from "../utils/createRequirePropertyRule.js";
+
+// List of all properties we want to create require- rules for,
+// in the format [propertyName, isRecommended]
+const properties = [
+	["author", false],
+	// TODO: More to come!
+] satisfies [string, boolean][];
+
+/** All require- flavor rules */
+export const rules = properties.reduce<Record<string, PackageJsonRuleModule>>(
+	(acc, [propertyName, isRecommended]) => {
+		acc[`require-${propertyName}`] = createRequirePropertyRule(
+			propertyName,
+			isRecommended,
+		);
+		return acc;
+	},
+	{},
+);

src/tests/rules/require-author.test.ts

@@ -0,0 +1,54 @@
+import { rules } from "../../rules/require-properties.js";
+import { ruleTester } from "./ruleTester.js";
+
+ruleTester.run("require-author", rules["require-author"], {
+	invalid: [
+		{
+			code: "{}",
+			errors: [
+				{
+					data: { property: "author" },
+					line: 1,
+					messageId: "missing",
+				},
+			],
+		},
+		{
+			code: `{
+            "name": "foo",
+            "version": "1.0.0"
+            }
+            `,
+			errors: [
+				{
+					data: { property: "author" },
+					line: 1,
+					messageId: "missing",
+				},
+			],
+		},
+		{
+			code: `{
+            "name": "foo",
+            "version": "1.0.0",
+            "bin": {
+                "author": "./cli.js"
+            }
+            }
+            `,
+			errors: [
+				{
+					data: { property: "author" },
+					line: 1,
+					messageId: "missing",
+				},
+			],
+		},
+	],
+	valid: [
+		`{ "main": "./index.js", "author": "Sophie Trudeau" }`,
+		`{ "author": "Jessica Moss" }`,
+		`{ "author": 123 }`,
+		`{ "author": { "name": "Jessica Moss" } }`,
+	],
+});

src/utils/createRequirePropertyRule.ts

@@ -0,0 +1,48 @@
+import type { AST as JsonAST } from "jsonc-eslint-parser";
+
+import { createRule } from "../createRule.js";
+import { isJSONStringLiteral } from "./predicates.js";
+
+/**
+ * Given a top-level property name, create a rule that requires that property to be present.
+ * Optionally, include it in the recommended config.
+ */
+export const createRequirePropertyRule = (
+	propertyName: string,
+	isRecommended = false,
+) => {
+	return createRule({
+		create(context) {
+			return {
+				"Program > JSONExpressionStatement > JSONObjectExpression"(
+					node: JsonAST.JSONObjectExpression,
+				) {
+					if (
+						!node.properties.some(
+							(property) =>
+								isJSONStringLiteral(property.key) &&
+								property.key.value === propertyName,
+						)
+					) {
+						context.report({
+							data: { property: propertyName },
+							messageId: "missing",
+							node: context.sourceCode.ast,
+						});
+					}
+				},
+			};
+		},
+		meta: {
+			docs: {
+				description: `Requires the \`${propertyName}\` property to be present.`,
+				recommended: isRecommended,
+			},
+			messages: {
+				missing: "Property '{{property}}' is required.",
+			},
+			schema: [],
+			type: "suggestion",
+		},
+	});
+};