Enable null safety

.travis.yml

@@ -19,5 +19,5 @@ dart_task:
 # Run tests on lowest supported SDK version.
 matrix:
   include:
-  - dart: 2.3.0
+  - dart: 2.12.0
     dart_task: test

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.4.0
+
+* Migrated to null safety.
+
 ## 0.3.0
 
 * Added an option to create case insensitive regular expressions.

example/main.dart

@@ -13,7 +13,7 @@ void main() {
 
   // Extract parameter arguments from a match.
   final match = regExp.matchAsPrefix('/user/12');
-  print(extract(parameters, match)); // {id: 12}
+  print(extract(parameters, match!)); // {id: 12}
 
   // Create a path function from tokens.
   final toPath = tokensToFunction(tokens);

lib/src/extract.dart

@@ -6,6 +6,6 @@ Map<String, String> extract(List<String> parameters, Match match) {
   final length = parameters.length;
   return {
     // Offset the group index by one since the first group is the entire match.
-    for (var i = 0; i < length; ++i) parameters[i]: match.group(i + 1)
+    for (var i = 0; i < length; ++i) parameters[i]: match.group(i + 1)!
   };
 }

lib/src/parse.dart

@@ -16,16 +16,19 @@ final _parameterRegExp = RegExp(
 /// Parses a [path] specification.
 ///
 /// Parameter names are added, in order, to [parameters] if provided.
-List<Token> parse(String path, {List<String> parameters}) {
+List<Token> parse(String path, {List<String>? parameters}) {
   final matches = _parameterRegExp.allMatches(path);
   final tokens = <Token>[];
   var start = 0;
   for (final match in matches) {
     if (match.start > start) {
       tokens.add(PathToken(path.substring(start, match.start)));
     }
-    final name = match[1];
-    final pattern = match[2] != null ? escapeGroup(match[2]) : _defaultPattern;
+    final name = match[1]!;
+    final optionalPattern = match[2];
+    final pattern = optionalPattern != null
+        ? escapeGroup(optionalPattern)
+        : _defaultPattern;
     tokens.add(ParameterToken(name, pattern: pattern));
     parameters?.add(name);
     start = match.end;

lib/src/regexp.dart

@@ -9,7 +9,7 @@ import 'token.dart';
 /// [caseSensitive] parameters and the return value.
 RegExp pathToRegExp(
   String path, {
-  List<String> parameters,
+  List<String>? parameters,
   bool prefix = false,
   bool caseSensitive = true,
 }) =>
@@ -33,7 +33,7 @@ RegExp tokensToRegExp(
   bool caseSensitive = true,
 }) {
   final buffer = StringBuffer('^');
-  String lastPattern;
+  String? lastPattern;
   for (final token in tokens) {
     lastPattern = token.toPattern();
     buffer.write(lastPattern);

lib/src/token.dart

@@ -19,13 +19,12 @@ class ParameterToken implements Token {
   final String pattern;
 
   /// The regular expression compiled from [pattern].
-  RegExp get regExp => _regExp ??= RegExp('^$pattern\$');
-  RegExp _regExp;
+  late final regExp = RegExp('^$pattern\$');
 
   @override
   String toPath(Map<String, String> args) {
-    if (args.containsKey(name)) {
-      final value = args[name];
+    final value = args[name];
+    if (value != null) {
       if (!regExp.hasMatch(value)) {
         throw ArgumentError.value('$args', 'args',
             'Expected "$name" to match "$pattern", but got "$value"');

pubspec.yaml

@@ -1,13 +1,12 @@
 name: path_to_regexp
-version: 0.3.0
+version: 0.4.0
 description: Converts a path such as '/user/:id' into a regular expression.
-author: Leon Senft <[email protected]>
 homepage: https://github.com/leonsenft/path_to_regexp
 
 environment:
-  sdk: ">=2.3.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dev_dependencies:
   # For `package:pedantic/analysis_options.yaml`.
-  pedantic: 1.8.0
-  test: ^1.3.0
+  pedantic: 1.11.0
+  test: ^1.16.5

test/path_to_regexp_test.dart

@@ -419,9 +419,8 @@ void tests(
       final match = parsedRegExp.matchAsPrefix(path);
       if (matchCase.matches) {
         test('should match "$path"', () {
-          expect(_groupsOf(match), matchCase.groups);
-        });
-        test('should extract arguments', () {
+          expect(match, isNotNull);
+          expect(_groupsOf(match!), matchCase.groups);
           expect(extract(parameters, match), matchCase.args);
         });
       } else {
@@ -449,7 +448,7 @@ void tests(
 List<String> _groupsOf(Match match) {
   return List<String>.generate(
     match.groupCount + 1,
-    (i) => match.group(i),
+    (i) => match.group(i)!,
     growable: false,
   );
 }
@@ -480,8 +479,8 @@ ToPathCase throws({Map<String, String> given = const {}}) =>
 class RegExpCase {
   RegExpCase(this.path, this.groups, this.args);
 
-  final Map<String, String> args;
-  final List<String> groups;
+  final Map<String, String>? args;
+  final List<String>? groups;
   final String path;
 
   bool get matches => groups != null;
@@ -491,5 +490,5 @@ class ToPathCase {
   ToPathCase(this.args, this.path);
 
   final Map<String, String> args;
-  final String path;
+  final String? path;
 }