diff --git a/apps/oxlint/src-js/plugins/context.ts b/apps/oxlint/src-js/plugins/context.ts
index bceefa51e587c..f0e37fda2742a 100644
--- a/apps/oxlint/src-js/plugins/context.ts
+++ b/apps/oxlint/src-js/plugins/context.ts
@@ -26,7 +26,7 @@
  * and global variables (`filePath`, `settings`, `cwd`).
  */
 
-import { ast, initAst, SOURCE_CODE } from "./source_code.ts";
+import { ast, initAst, fileIsJsx, SOURCE_CODE } from "./source_code.ts";
 import { report } from "./report.ts";
 import { settings, initSettings } from "./settings.ts";
 import visitorKeys from "../generated/keys.ts";
@@ -143,6 +143,13 @@ export const ecmaFeaturesOverride: {
 
 // Singleton object for ECMA features.
 const ECMA_FEATURES = Object.freeze({
+  /**
+   * `true` if file was parsed as JSX.
+   */
+  get jsx(): boolean {
+    return fileIsJsx();
+  },
+
   /**
    * `true` if file was parsed with top-level `return` statements allowed.
    */
diff --git a/apps/oxlint/src-js/plugins/source_code.ts b/apps/oxlint/src-js/plugins/source_code.ts
index f73d23ba83ac5..70e93cc35aa47 100644
--- a/apps/oxlint/src-js/plugins/source_code.ts
+++ b/apps/oxlint/src-js/plugins/source_code.ts
@@ -2,6 +2,8 @@ import {
   DATA_POINTER_POS_32,
   SOURCE_START_OFFSET,
   SOURCE_LEN_OFFSET,
+  IS_JSX_FLAG_POS,
+  IS_TS_FLAG_POS,
 } from "../generated/constants.ts";
 
 // We use the deserializer which removes `ParenthesizedExpression`s from AST,
@@ -29,7 +31,7 @@ import type { ScopeManager } from "./scope.ts";
 const textDecoder = new TextDecoder("utf-8", { ignoreBOM: true });
 
 // Buffer containing AST. Set before linting a file by `setupSourceForFile`.
-export let buffer: BufferWithArrays | null = null;
+let buffer: BufferWithArrays | null = null;
 
 // Indicates if the original source text has a BOM. Set before linting a file by `setupSourceForFile`.
 let hasBOM = false;
@@ -105,6 +107,26 @@ export function resetSourceAndAst(): void {
   resetTokens();
 }
 
+/**
+ * Get whether file is JSX.
+ * @returns `true` if file is JSX, `false` if not
+ */
+export function fileIsJsx(): boolean {
+  debugAssertIsNonNull(buffer);
+  // Flag is `bool` in Rust, so 0 = false, 1 = true
+  return buffer[IS_JSX_FLAG_POS] === 1;
+}
+
+/**
+ * Get whether file is TypeScript.
+ * @returns `true` if file is TypeScript, `false` if not
+ */
+export function fileIsTs(): boolean {
+  debugAssertIsNonNull(buffer);
+  // Flag is `bool` in Rust, so 0 = false, 1 = true
+  return buffer[IS_TS_FLAG_POS] === 1;
+}
+
 // `SourceCode` object.
 //
 // Only one file is linted at a time, so we can reuse a single object for all files.
diff --git a/apps/oxlint/src-js/plugins/tokens_parse.ts b/apps/oxlint/src-js/plugins/tokens_parse.ts
index 0e4671ecb2018..88068bde3aa26 100644
--- a/apps/oxlint/src-js/plugins/tokens_parse.ts
+++ b/apps/oxlint/src-js/plugins/tokens_parse.ts
@@ -5,8 +5,7 @@
 import { createRequire } from "node:module";
 import { filePath } from "./context.ts";
 import { getNodeLoc } from "./location.ts";
-import { buffer, sourceText } from "./source_code.ts";
-import { IS_JSX_FLAG_POS, IS_TS_FLAG_POS } from "../generated/constants.ts";
+import { sourceText, fileIsJsx, fileIsTs } from "./source_code.ts";
 import { debugAssert, debugAssertIsNonNull } from "../utils/asserts.ts";
 
 import type * as ts from "typescript";
@@ -41,7 +40,6 @@ const TokenProto = Object.create(Object.prototype, {
 export function parseTokens(): Token[] {
   debugAssertIsNonNull(filePath);
   debugAssertIsNonNull(sourceText);
-  debugAssertIsNonNull(buffer);
 
   // Lazy-load TypeScript.
   // `./typescript.cjs` is path to the bundle in `dist` directory, as well as relative path in `src-js`,
@@ -53,16 +51,12 @@ export function parseTokens(): Token[] {
     tsSyntaxKind = tsModule.SyntaxKind;
   }
 
-  // Get source type from flags in buffer.
-  // Both flags are `bool`s in Rust, so 0 = false, 1 = true.
-  const isTs = buffer[IS_TS_FLAG_POS] === 1,
-    isJsx = buffer[IS_JSX_FLAG_POS] === 1;
-
-  const scriptKind = isTs
-    ? isJsx
+  // Determine language from flags in buffer
+  const scriptKind = fileIsTs()
+    ? fileIsJsx()
       ? tsModule.ScriptKind.TSX
       : tsModule.ScriptKind.TS
-    : isJsx
+    : fileIsJsx()
       ? tsModule.ScriptKind.JSX
       : tsModule.ScriptKind.JS;
 
diff --git a/apps/oxlint/test/fixtures/languageOptions/files/index.ts b/apps/oxlint/test/fixtures/languageOptions/files/index.ts
new file mode 100644
index 0000000000000..2756c24c45775
--- /dev/null
+++ b/apps/oxlint/test/fixtures/languageOptions/files/index.ts
@@ -0,0 +1 @@
+let x;
diff --git a/apps/oxlint/test/fixtures/languageOptions/output.snap.md b/apps/oxlint/test/fixtures/languageOptions/output.snap.md
index 72f5af13c481c..2e320c03fba62 100644
--- a/apps/oxlint/test/fixtures/languageOptions/output.snap.md
+++ b/apps/oxlint/test/fixtures/languageOptions/output.snap.md
@@ -6,7 +6,7 @@
   x language-options-plugin(lang): languageOptions:
   | sourceType: commonjs
   | ecmaVersion: 2026
-  | parserOptions: {"sourceType":"commonjs","ecmaFeatures":{"globalReturn":true,"impliedStrict":false}}
+  | parserOptions: {"sourceType":"commonjs","ecmaFeatures":{"jsx":true,"globalReturn":true,"impliedStrict":false}}
   | globals: {}
   | env: {"builtin":true}
    ,-[files/index.cjs:1:1]
@@ -794,7 +794,7 @@
   x language-options-plugin(lang): languageOptions:
   | sourceType: script
   | ecmaVersion: 2026
-  | parserOptions: {"sourceType":"script","ecmaFeatures":{"globalReturn":false,"impliedStrict":false}}
+  | parserOptions: {"sourceType":"script","ecmaFeatures":{"jsx":true,"globalReturn":false,"impliedStrict":false}}
   | globals: {}
   | env: {"builtin":true}
    ,-[files/index.js:1:1]
@@ -805,7 +805,7 @@
   x language-options-plugin(lang): languageOptions:
   | sourceType: module
   | ecmaVersion: 2026
-  | parserOptions: {"sourceType":"module","ecmaFeatures":{"globalReturn":false,"impliedStrict":true}}
+  | parserOptions: {"sourceType":"module","ecmaFeatures":{"jsx":true,"globalReturn":false,"impliedStrict":true}}
   | globals: {}
   | env: {"builtin":true}
    ,-[files/index.mjs:1:1]
@@ -813,8 +813,19 @@
    : ^
    `----
 
-Found 0 warnings and 4 errors.
-Finished in Xms on 3 files with 1 rules using X threads.
+  x language-options-plugin(lang): languageOptions:
+  | sourceType: script
+  | ecmaVersion: 2026
+  | parserOptions: {"sourceType":"script","ecmaFeatures":{"jsx":false,"globalReturn":false,"impliedStrict":false}}
+  | globals: {}
+  | env: {"builtin":true}
+   ,-[files/index.ts:1:1]
+ 1 | let x;
+   : ^
+   `----
+
+Found 0 warnings and 5 errors.
+Finished in Xms on 4 files with 1 rules using X threads.
 ```
 
 # stderr