From b20f2a25a523794de68fb4416e885697b2d46dfb Mon Sep 17 00:00:00 2001
From: Vladislav Mamon <norskeld@gmail.com>
Date: Thu, 5 Jan 2023 13:34:06 +0300
Subject: [PATCH] fix(parsers/oneOf): halt at reaching eoi

---
 src/__tests__/parsers/oneOf.spec.ts | 7 ++++++-
 src/parsers/oneOf.ts                | 8 ++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/__tests__/parsers/oneOf.spec.ts b/src/__tests__/parsers/oneOf.spec.ts
index a953bda..9a2efae 100644
--- a/src/__tests__/parsers/oneOf.spec.ts
+++ b/src/__tests__/parsers/oneOf.spec.ts
@@ -1,4 +1,5 @@
-import { oneOf } from '@parsers'
+import { sequence } from '@combinators'
+import { string, oneOf } from '@parsers'
 import { run, result, should, describe, testFailure, it } from '@testing'
 
 describe('oneOf', () => {
@@ -12,4 +13,8 @@ describe('oneOf', () => {
   it('should fail if input character is not among given ones', () => {
     testFailure('q-combinator', oneOf('xyz'))
   })
+
+  it('should fail if reached the end of input', () => {
+    testFailure('prefix', sequence(string('prefix'), oneOf('XY')))
+  })
 })
diff --git a/src/parsers/oneOf.ts b/src/parsers/oneOf.ts
index a773bed..477bc30 100644
--- a/src/parsers/oneOf.ts
+++ b/src/parsers/oneOf.ts
@@ -12,6 +12,14 @@ export function oneOf(chars: string): Parser<string> {
 
   return {
     parse(input, pos) {
+      if (input.length === pos) {
+        return {
+          isOk: false,
+          pos,
+          expected: 'oneOf @ reached the end of input'
+        }
+      }
+
       const nextPos = pos + 1
       const char = input.substring(pos, nextPos)