feat: rule no-unnormalized-keys (#63)

* feat: rule no-unormalized-keys

Fixes #32

* Add no-unnormalized-keys to plugin exports

* Cleanup tests and refactor for clarity

* Output key into error message and update tests

* Update README

* Switch to object option

* Re-add eslint.test.js

* Update src/rules/no-unnormalized-keys.js

Co-authored-by: Milos Djermanovic <[email protected]>

* Update src/rules/no-unnormalized-keys.js

Co-authored-by: Milos Djermanovic <[email protected]>

---------

Co-authored-by: Bradley Meck Farias <[email protected]>
Co-authored-by: Milos Djermanovic <[email protected]>

Author: 3 people

README.md

@@ -155,6 +155,7 @@ export default [
 -   `no-duplicate-keys` - warns when there are two keys in an object with the same text.
 -   `no-empty-keys` - warns when there is a key in an object that is an empty string or contains only whitespace (note: `package-lock.json` uses empty keys intentionally)
 -   `no-unsafe-values` - warns on values that are unsafe for interchange, such as numbers outside safe range or lone surrogates.
+-   `no-unnormalized-keys` - warns on keys containing [unnormalized characters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize#description). You can optionally specify the normalization form via `{ form: "form_name" }`, where `form_name` can be any of `"NFC"`, `"NFD"`, `"NFKC"`, or `"NFKD"`.
 
 ## Configuration Comments
 

src/index.js

@@ -12,6 +12,7 @@ import { JSONSourceCode } from "./languages/json-source-code.js";
 import noDuplicateKeys from "./rules/no-duplicate-keys.js";
 import noEmptyKeys from "./rules/no-empty-keys.js";
 import noUnsafeValues from "./rules/no-unsafe-values.js";
+import noUnnormalizedKeys from "./rules/no-unnormalized-keys.js";
 
 //-----------------------------------------------------------------------------
 // Plugin
@@ -31,6 +32,7 @@ const plugin = {
 		"no-duplicate-keys": noDuplicateKeys,
 		"no-empty-keys": noEmptyKeys,
 		"no-unsafe-values": noUnsafeValues,
+		"no-unnormalized-keys": noUnnormalizedKeys,
 	},
 	configs: {
 		recommended: {
@@ -39,6 +41,7 @@ const plugin = {
 				"json/no-duplicate-keys": "error",
 				"json/no-empty-keys": "error",
 				"json/no-unsafe-values": "error",
+				"json/no-unnormalized-keys": "error",
 			}),
 		},
 	},

src/rules/no-unnormalized-keys.js

@@ -0,0 +1,54 @@
+/**
+ * @fileoverview Rule to detect unnormalized keys in JSON.
+ * @author Bradley Meck Farias
+ */
+
+export default {
+	meta: {
+		type: /** @type {const} */ ("problem"),
+
+		docs: {
+			description: "Disallow JSON keys that are not normalized",
+		},
+
+		messages: {
+			unnormalizedKey: "Unnormalized key '{{key}}' found.",
+		},
+
+		schema: [
+			{
+				type: "object",
+				properties: {
+					form: {
+						enum: ["NFC", "NFD", "NFKC", "NFKD"],
+					},
+				},
+				additionalProperties: false,
+			},
+		],
+	},
+
+	create(context) {
+		const normalization = context.options.length
+			? text => text.normalize(context.options[0].form)
+			: text => text.normalize();
+		return {
+			Member(node) {
+				const key =
+					node.name.type === "String"
+						? node.name.value
+						: node.name.name;
+
+				if (normalization(key) !== key) {
+					context.report({
+						loc: node.name.loc,
+						messageId: "unnormalizedKey",
+						data: {
+							key,
+						},
+					});
+				}
+			},
+		};
+	},
+};

tests/rules/no-unnormalized-keys.test.js

@@ -0,0 +1,90 @@
+/**
+ * @fileoverview Tests for no-unnormalized-keys rule.
+ * @author Bradley Meck Farias
+ */
+
+//------------------------------------------------------------------------------
+// Imports
+//------------------------------------------------------------------------------
+
+import rule from "../../src/rules/no-unnormalized-keys.js";
+import json from "../../src/index.js";
+import { RuleTester } from "eslint";
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+const ruleTester = new RuleTester({
+	plugins: {
+		json,
+	},
+	language: "json/json",
+});
+
+const o = "\u1E9B\u0323";
+
+ruleTester.run("no-unnormalized-keys", rule, {
+	valid: [
+		`{"${o}":"NFC"}`,
+		{
+			code: `{"${o}":"NFC"}`,
+			options: [{ form: "NFC" }],
+		},
+		{
+			code: `{"${o.normalize("NFD")}":"NFD"}`,
+			options: [{ form: "NFD" }],
+		},
+		{
+			code: `{"${o.normalize("NFKC")}":"NFKC"}`,
+			options: [{ form: "NFKC" }],
+		},
+		{
+			code: `{"${o.normalize("NFKD")}":"NFKD"}`,
+			options: [{ form: "NFKD" }],
+		},
+	],
+	invalid: [
+		{
+			code: `{"${o.normalize("NFD")}":"NFD"}`,
+			errors: [
+				{
+					messageId: "unnormalizedKey",
+					data: { key: o.normalize("NFD") },
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 7,
+				},
+			],
+		},
+		{
+			code: `{${o.normalize("NFD")}:"NFD"}`,
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "unnormalizedKey",
+					data: { key: o.normalize("NFD") },
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 5,
+				},
+			],
+		},
+		{
+			code: `{"${o.normalize("NFKC")}":"NFKC"}`,
+			options: [{ form: "NFKD" }],
+			errors: [
+				{
+					messageId: "unnormalizedKey",
+					data: { key: o.normalize("NFKC") },
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 5,
+				},
+			],
+		},
+	],
+});