Expose isPatternValid and assertPatternValid helpers (#15)

Author: fregante

index.ts

@@ -3,17 +3,25 @@ import escapeStringRegexp from 'escape-string-regexp';
 // Copied from https://github.com/mozilla/gecko-dev/blob/073cc24f53d0cf31403121d768812146e597cc9d/toolkit/components/extensions/schemas/manifest.json#L487-L491
 export const patternValidationRegex = /^(https?|wss?|file|ftp|\*):\/\/(\*|\*\.[^*/]+|[^*/]+)\/.*$|^file:\/\/\/.*$|^resource:\/\/(\*|\*\.[^*/]+|[^*/]+)\/.*$|^about:/;
 
-const isFirefox = typeof navigator === 'object' && navigator.userAgent.includes('Firefox/');
+const isFirefox = globalThis.navigator?.userAgent.includes('Firefox/');
 
 export const allStarsRegex = isFirefox
 	? /^(https?|wss?):[/][/][^/]+([/].*)?$/
 	: /^https?:[/][/][^/]+([/].*)?$/;
 export const allUrlsRegex = /^(https?|file|ftp):[/]+/;
 
-function getRawPatternRegex(matchPattern: string): string {
-	if (!patternValidationRegex.test(matchPattern)) {
+export function assertValidPattern(matchPattern: string): void {
+	if (!isValidPattern(matchPattern)) {
 		throw new Error(matchPattern + ' is an invalid pattern, it must match ' + String(patternValidationRegex));
 	}
+}
+
+export function isValidPattern(matchPattern: string): boolean {
+	return matchPattern === '<all_urls>' || patternValidationRegex.test(matchPattern);
+}
+
+function getRawPatternRegex(matchPattern: string): string {
+	assertValidPattern(matchPattern);
 
 	// Host undefined for file:///
 	let [, protocol, host = '', pathname] = matchPattern.split(/(^[^:]+:[/][/])([^/]+)?/);

readme.md

@@ -19,7 +19,13 @@ npm install webext-patterns
 
 ```js
 // This module is only offered as a ES Module
-import {patternToRegex} from 'webext-patterns';
+import {
+	patternToRegex,
+	globToRegex,
+	excludeDuplicatePatterns
+	assertValidPattern,
+	isValidPattern,
+} from 'webext-patterns';
 ```
 
 ## Usage
@@ -33,6 +39,12 @@ globToRegex('*.example.com');
 
 excludeDuplicatePatterns(['https://*.google.com/*', 'https://google.com/*']);
 // Returns ['https://*.google.com/*']
+
+assertValidPattern('https://google.*/*');
+// Throws an error because the pattern is invalid
+
+isValidPattern('https://*.google.com/*');
+// Returns true
 ```
 
 > **Note**
@@ -100,6 +112,24 @@ excludeDuplicatePatterns([
 // Returns ["https://*/*"]
 ```
 
+#### assertValidPattern(pattern)
+
+Accepts a pattern and throws an error if it's invalid.
+
+```js
+assertValidPattern('https://google.*/*');
+// Throws an error because the pattern is invalid
+```
+
+#### isValidPattern(pattern)
+
+Accepts a pattern and returns `true` if it's valid.
+
+```js
+isValidPattern('https://google.*/*');
+// Returns false
+```
+
 ## Related
 
 ### Permissions

test/patterns.js

@@ -1,10 +1,12 @@
 import test from 'ava';
-import {patternToRegex} from '../index.js';
+import {patternToRegex, isValidPattern, assertValidPattern} from '../index.js';
 
 function macro(t, pattern, matching) {
 	const regex = patternToRegex(pattern);
 	for (const url of matching) {
 		t.regex(url, regex);
+		t.true(isValidPattern(pattern));
+		t.notThrows(() => assertValidPattern(pattern));
 	}
 }
 
@@ -65,6 +67,7 @@ test('Should not match anything if no patterns are passed', t => {
 });
 
 const invalidPatterns = [
+	'https://google.*/*', // The TLD cannot be a wildcard
 	'https://mozilla.org', // No path
 	'https://*zilla.org/', // "*" in host must be the only character or be followed by "."
 	'http*://mozilla.org/', // "*" in scheme must be the only character
@@ -74,9 +77,15 @@ const invalidPatterns = [
 ];
 for (const pattern of invalidPatterns) {
 	test('Invalid pattern: ' + pattern, t => {
+		t.false(isValidPattern(pattern));
+
 		t.throws(() => patternToRegex(pattern), {
 			message: /is an invalid pattern, it must match/,
 		});
+
+		t.throws(() => assertValidPattern(pattern), {
+			message: /is an invalid pattern, it must match/,
+		});
 	});
 }