fix: reject invalid escape sequences in JSON Pointer strings (#13)

* fix: reject invalid escape sequences in JSON Pointer strings

* refactor: use RegExp.test instead of String.search for escape validation

Author: AhmedHanyGamal

lib/index.js

@@ -10,6 +10,10 @@ export const pointerSegments = function* (pointer) {
     throw Error("Invalid JSON Pointer");
   }
 
+  if (/~(?![01])/.test(pointer)) {
+    throw Error("Invalid JSON Pointer");
+  }
+
   let segmentStart = 1;
   let segmentEnd = 0;
 

lib/pointerSegments.test.js

@@ -0,0 +1,60 @@
+import { describe, expect, test } from "vitest";
+import { pointerSegments } from "./index.js";
+
+
+describe("JsonPointer", () => {
+  describe("pointerSegments", () => {
+    /** @type [string, string[]][] */
+    const tests = [
+      ["", []],
+      ["/", [""]],
+      ["/foo", ["foo"]],
+      ["/foo/bar", ["foo", "bar"]],
+      ["/foo/0", ["foo", "0"]],
+      ["/a~1b", ["a/b"]],
+      ["/m~0n", ["m~n"]],
+      ["/~00", ["~0"]],
+      ["/~01", ["~1"]],
+      ["/~10", ["/0"]],
+      ["/~11", ["/1"]],
+      ["/~01~10", ["~1/0"]],
+      ["/~00/~11", ["~0", "/1"]],
+      ["/ ", [" "]],
+      ["/c%d", ["c%d"]],
+      ["/e^f", ["e^f"]],
+      ["/g|h", ["g|h"]],
+      ["/i\\j", ["i\\j"]],
+      ["/k\"l", ["k\"l"]]
+    ];
+
+    tests.forEach(([pointer, expected]) => {
+      test(`${JSON.stringify(pointer)} => ${JSON.stringify(expected)}`, () => {
+        expect([...pointerSegments(pointer)]).to.eql(expected);
+      });
+    });
+  });
+
+  describe("a pointer that doesn't start with '/'", () => {
+    test("should throw an error", () => {
+      expect(() => [...pointerSegments("foo")]).to.throw(Error, "Invalid JSON Pointer");
+    });
+  });
+
+  describe("a pointer with an invalid escape sequence", () => {
+    /** @type string[] */
+    const tests = [
+      "/~",
+      "/~2",
+      "/~a",
+      "/a~",
+      "/~~",
+      "/~0~"
+    ];
+
+    tests.forEach((pointer) => {
+      test(`${JSON.stringify(pointer)} should throw an error`, () => {
+        expect(() => [...pointerSegments(pointer)]).to.throw(Error, "Invalid JSON Pointer");
+      });
+    });
+  });
+});