Add custom error class (#398)

Author: blakeembrey

src/index.spec.ts

@@ -6,6 +6,7 @@ import {
   stringify,
   pathToRegexp,
   TokenData,
+  PathError,
 } from "./index.js";
 import {
   PARSER_TESTS,
@@ -18,44 +19,62 @@ import {
  * Dynamically generate the entire test suite.
  */
 describe("path-to-regexp", () => {
+  describe("ParseError", () => {
+    it("should contain original path and debug url", () => {
+      const error = new PathError(
+        "Unexpected END at index 7, expected }",
+        "/{:foo,",
+      );
+
+      expect(error).toBeInstanceOf(TypeError);
+      expect(error.message).toBe(
+        "Unexpected END at index 7, expected }: /{:foo,; visit https://git.new/pathToRegexpError for info",
+      );
+      expect(error.originalPath).toBe("/{:foo,");
+    });
+
+    it("should omit original url when undefined", () => {
+      const error = new PathError(
+        "Unexpected END at index 7, expected }",
+        undefined,
+      );
+
+      expect(error).toBeInstanceOf(TypeError);
+      expect(error.message).toBe(
+        "Unexpected END at index 7, expected }; visit https://git.new/pathToRegexpError for info",
+      );
+      expect(error.originalPath).toBeUndefined();
+    });
+  });
+
   describe("parse errors", () => {
     it("should throw on unbalanced group", () => {
       expect(() => parse("/{:foo,")).toThrow(
-        new TypeError(
-          "Unexpected END at index 7, expected }: /{:foo,; visit https://git.new/pathToRegexpError for info",
-        ),
+        new PathError("Unexpected END at index 7, expected }", "/{:foo,"),
       );
     });
 
     it("should throw on nested unbalanced group", () => {
       expect(() => parse("/{:foo/{x,y}")).toThrow(
-        new TypeError(
-          "Unexpected END at index 12, expected }: /{:foo/{x,y}; visit https://git.new/pathToRegexpError for info",
-        ),
+        new PathError("Unexpected END at index 12, expected }", "/{:foo/{x,y}"),
       );
     });
 
     it("should throw on missing param name", () => {
       expect(() => parse("/:/")).toThrow(
-        new TypeError(
-          "Missing parameter name at index 2: /:/; visit https://git.new/pathToRegexpError for info",
-        ),
+        new PathError("Missing parameter name at index 2", "/:/"),
       );
     });
 
     it("should throw on missing wildcard name", () => {
       expect(() => parse("/*/")).toThrow(
-        new TypeError(
-          "Missing parameter name at index 2: /*/; visit https://git.new/pathToRegexpError for info",
-        ),
+        new PathError("Missing parameter name at index 2", "/*/"),
       );
     });
 
     it("should throw on unterminated quote", () => {
       expect(() => parse('/:"foo')).toThrow(
-        new TypeError(
-          'Unterminated quote at index 2: /:"foo; visit https://git.new/pathToRegexpError for info',
-        ),
+        new PathError("Unterminated quote at index 2", '/:"foo'),
       );
     });
   });
@@ -105,9 +124,7 @@ describe("path-to-regexp", () => {
   describe("pathToRegexp errors", () => {
     it("should throw when missing text between params", () => {
       expect(() => pathToRegexp("/:foo:bar")).toThrow(
-        new TypeError(
-          'Missing text before "bar": /:foo:bar; visit https://git.new/pathToRegexpError for info',
-        ),
+        new PathError('Missing text before "bar" param', "/:foo:bar"),
       );
     });
 
@@ -119,11 +136,7 @@ describe("path-to-regexp", () => {
             { type: "param", name: "b" },
           ]),
         ),
-      ).toThrow(
-        new TypeError(
-          'Missing text before "b"; visit https://git.new/pathToRegexpError for info',
-        ),
-      );
+      ).toThrow(new PathError('Missing text before "b" param', undefined));
     });
 
     it("should throw with `originalPath` when missing text between params using TokenData", () => {
@@ -137,11 +150,7 @@ describe("path-to-regexp", () => {
             "/[a][b]",
           ),
         ),
-      ).toThrow(
-        new TypeError(
-          'Missing text before "b": /[a][b]; visit https://git.new/pathToRegexpError for info',
-        ),
-      );
+      ).toThrow(new PathError('Missing text before "b" param', "/[a][b]"));
     });
 
     it("should contain the error line", () => {

src/index.ts

@@ -2,7 +2,6 @@ const DEFAULT_DELIMITER = "/";
 const NOOP_VALUE = (value: string) => value;
 const ID_START = /^[$_\p{ID_Start}]$/u;
 const ID_CONTINUE = /^[$\u200c\u200d\p{ID_Continue}]$/u;
-const DEBUG_URL = "https://git.new/pathToRegexpError";
 
 /**
  * Encode a string into another string.
@@ -112,16 +111,6 @@ function escape(str: string) {
   return str.replace(/[.+*?^${}()[\]|/\\]/g, "\\$&");
 }
 
-/**
- * Format error so it's easier to debug.
- */
-function errorMessage(text: string, originalPath: string | undefined) {
-  let message = text;
-  if (originalPath !== undefined) message += `: ${originalPath}`;
-  message += `; visit ${DEBUG_URL} for info`;
-  return message;
-}
-
 /**
  * Plain text.
  */
@@ -179,6 +168,21 @@ export class TokenData {
   ) {}
 }
 
+/**
+ * ParseError is thrown when there is an error processing the path.
+ */
+export class PathError extends TypeError {
+  constructor(
+    message: string,
+    public readonly originalPath: string | undefined,
+  ) {
+    let text = message;
+    if (originalPath) text += `: ${originalPath}`;
+    text += `; visit https://git.new/pathToRegexpError for info`;
+    super(text);
+  }
+}
+
 /**
  * Parse a string for the raw tokens.
  */
@@ -215,16 +219,12 @@ export function parse(str: string, options: ParseOptions = {}): TokenData {
       }
 
       if (pos) {
-        throw new TypeError(
-          errorMessage(`Unterminated quote at index ${pos}`, str),
-        );
+        throw new PathError(`Unterminated quote at index ${pos}`, str);
       }
     }
 
     if (!value) {
-      throw new TypeError(
-        errorMessage(`Missing parameter name at index ${index}`, str),
-      );
+      throw new PathError(`Missing parameter name at index ${index}`, str);
     }
 
     return value;
@@ -292,11 +292,9 @@ export function parse(str: string, options: ParseOptions = {}): TokenData {
         continue;
       }
 
-      throw new TypeError(
-        errorMessage(
-          `Unexpected ${type} at index ${index}, expected ${endType}`,
-          str,
-        ),
+      throw new PathError(
+        `Unexpected ${type} at index ${index}, expected ${endType}`,
+        str,
       );
     }
 
@@ -564,8 +562,9 @@ function toRegExpSource(
 
     if (token.type === "param" || token.type === "wildcard") {
       if (!isSafeSegmentParam && !backtrack) {
-        throw new TypeError(
-          errorMessage(`Missing text before "${token.name}"`, originalPath),
+        throw new PathError(
+          `Missing text before "${token.name}" ${token.type}`,
+          originalPath,
         );
       }