feat: add support for getLocFromIndex and getIndexFromLoc (#376)

* feat: add support for `getLocFromIndex`

* wip: migration

* wip: bump dependencies

* wip

* wip: add type test

* wip: tests

Author: lumirlumir

package.json

@@ -73,23 +73,23 @@
     "test:types": "tsc -p tests/types/tsconfig.json"
   },
   "devDependencies": {
-    "@eslint/js": "^9.31.0",
-    "@eslint/json": "^0.13.1",
+    "@eslint/js": "^9.36.0",
+    "@eslint/json": "^0.13.2",
     "c8": "^10.1.3",
     "dedent": "^1.5.3",
-    "eslint": "^9.35.0",
+    "eslint": "^9.36.0",
     "eslint-config-eslint": "^13.0.0",
     "eslint-plugin-eslint-plugin": "^6.3.2",
-    "globals": "^16.0.0",
+    "globals": "^16.4.0",
     "lint-staged": "^15.2.9",
     "mocha": "^11.6.0",
     "prettier": "^3.3.3",
     "typescript": "^5.9.2",
     "yorkie": "^2.0.0"
   },
   "dependencies": {
-    "@eslint/core": "^0.15.2",
-    "@eslint/plugin-kit": "^0.3.5",
+    "@eslint/core": "^0.16.0",
+    "@eslint/plugin-kit": "^0.4.0",
     "github-slugger": "^2.0.0",
     "mdast-util-from-markdown": "^2.0.2",
     "mdast-util-frontmatter": "^2.0.1",

tests/language/markdown-source-code.test.js

@@ -104,6 +104,132 @@ describe("MarkdownSourceCode", () => {
 		});
 	});
 
+	describe("getLocFromIndex()", () => {
+		it("should convert index to location correctly", () => {
+			const text = "foo\nbar\r\nbaz";
+			const markdownSourceCode = new MarkdownSourceCode({
+				text,
+				ast: fromMarkdown(text),
+			});
+
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(0), {
+				line: 1,
+				column: 1,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(1), {
+				line: 1,
+				column: 2,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(2), {
+				line: 1,
+				column: 3,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(3), {
+				line: 1,
+				column: 4,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(4), {
+				line: 2,
+				column: 1,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(5), {
+				line: 2,
+				column: 2,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(6), {
+				line: 2,
+				column: 3,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(7), {
+				line: 2,
+				column: 4,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(8), {
+				line: 2,
+				column: 5,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(9), {
+				line: 3,
+				column: 1,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(10), {
+				line: 3,
+				column: 2,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(11), {
+				line: 3,
+				column: 3,
+			});
+			assert.deepStrictEqual(markdownSourceCode.getLocFromIndex(12), {
+				line: 3,
+				column: 4,
+			});
+		});
+	});
+
+	describe("getIndexFromLoc()", () => {
+		it("should convert location to index correctly", () => {
+			const text = "foo\nbar\r\nbaz";
+			const markdownSourceCode = new MarkdownSourceCode({
+				text,
+				ast: fromMarkdown(text),
+			});
+
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 1, column: 1 }),
+				0,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 1, column: 2 }),
+				1,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 1, column: 3 }),
+				2,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 1, column: 4 }),
+				3,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 2, column: 1 }),
+				4,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 2, column: 2 }),
+				5,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 2, column: 3 }),
+				6,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 2, column: 4 }),
+				7,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 2, column: 5 }),
+				8,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 3, column: 1 }),
+				9,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 3, column: 2 }),
+				10,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 3, column: 3 }),
+				11,
+			);
+			assert.strictEqual(
+				markdownSourceCode.getIndexFromLoc({ line: 3, column: 4 }),
+				12,
+			);
+		});
+	});
+
 	describe("getInlineConfigNodes()", () => {
 		it("should return the inline config nodes", () => {
 			const nodes = sourceCode.getInlineConfigNodes();

tests/types/types.test.ts

@@ -136,6 +136,11 @@ typeof processorPlugins satisfies {};
 			parent?: Parent | undefined,
 		) {
 			sourceCode.getLoc(node) satisfies SourceLocation;
+			sourceCode.getLocFromIndex(0) satisfies {
+				line: number;
+				column: number;
+			};
+			sourceCode.getIndexFromLoc({ line: 1, column: 1 }) satisfies number;
 			sourceCode.getRange(node) satisfies SourceRange;
 			sourceCode.getParent(node) satisfies Node | undefined;
 			sourceCode.getAncestors(node) satisfies Node[];