Error on trailing backslash (#434)

Author: blakeembrey

src/index.spec.ts

@@ -19,7 +19,7 @@ import {
  * Dynamically generate the entire test suite.
  */
 describe("path-to-regexp", () => {
-  describe("ParseError", () => {
+  describe("PathError", () => {
     it("should contain original path and debug url", () => {
       const error = new PathError(
         "Unexpected end at index 7, expected }",
@@ -77,6 +77,36 @@ describe("path-to-regexp", () => {
         new PathError("Unterminated quote at index 2", '/:"foo'),
       );
     });
+
+    it("should throw on eol backslash", () => {
+      expect(() => parse("/foo\\")).toThrow(
+        new PathError("Unexpected end after \\ at index 5", "/foo\\"),
+      );
+    });
+
+    it("should throw on eol backslash in group", () => {
+      expect(() => parse("/foo/{bar\\")).toThrow(
+        new PathError("Unexpected end after \\ at index 10", "/foo/{bar\\"),
+      );
+    });
+
+    it("should throw on eol backslash after param", () => {
+      expect(() => parse("/foo/:bar\\")).toThrow(
+        new PathError("Unexpected end after \\ at index 10", "/foo/:bar\\"),
+      );
+    });
+
+    it("should throw on eol backslash after wildcard", () => {
+      expect(() => parse("/foo/*bar\\")).toThrow(
+        new PathError("Unexpected end after \\ at index 10", "/foo/*bar\\"),
+      );
+    });
+
+    it("should throw on eol backslash in quoted param", () => {
+      expect(() => parse('/foo/:"bar\\')).toThrow(
+        new PathError("Unterminated quote at index 6", '/foo/:"bar\\'),
+      );
+    });
   });
 
   describe("compile errors", () => {

src/index.ts

@@ -64,7 +64,6 @@ type TokenType =
   | "wildcard"
   | "param"
   | "char"
-  | "escape"
   | "end"
   // Reserved for use or ambiguous due to past use.
   | "("
@@ -220,10 +219,14 @@ export function parse(str: string, options: ParseOptions = {}): TokenData {
   while (index < chars.length) {
     const value = chars[index++];
 
-    if (SIMPLE_TOKENS.includes(value)) {
+    if (value === "\\") {
+      if (index === chars.length) {
+        throw new PathError(`Unexpected end after \\ at index ${index}`, str);
+      }
+
+      tokens.push({ type: "char", index, value: chars[index++] });
+    } else if (SIMPLE_TOKENS.includes(value)) {
       tokens.push({ type: value as TokenType, index, value });
-    } else if (value === "\\") {
-      tokens.push({ type: "escape", index, value: chars[index++] });
     } else if (value === ":") {
       tokens.push({ type: "param", index, value: name() });
     } else if (value === "*") {
@@ -242,11 +245,11 @@ export function parse(str: string, options: ParseOptions = {}): TokenData {
       const token = tokens[pos++];
       if (token.type === endType) break;
 
-      if (token.type === "char" || token.type === "escape") {
+      if (token.type === "char") {
         let path = token.value;
         let cur = tokens[pos];
 
-        while (cur.type === "char" || cur.type === "escape") {
+        while (cur.type === "char") {
           path += cur.value;
           cur = tokens[++pos];
         }