Use Collection Expressions in the library (#613)

* Use Collection Expressions

Mostly cleaning up default values

* In more places

Author: abergs

Src/Fido2.Development/DevelopmentInMemoryStore.cs

@@ -51,7 +51,7 @@ public Task<List<Fido2User>> GetUsersByCredentialIdAsync(byte[] credentialId, Ca
         var cred = _storedCredentials.FirstOrDefault(c => c.Descriptor.Id.AsSpan().SequenceEqual(credentialId));
 
         if (cred is null)
-            return Task.FromResult(new List<Fido2User>());
+            return Task.FromResult<List<Fido2User>>([]);
 
         return Task.FromResult(_storedUsers.Where(u => u.Value.Id.SequenceEqual(cred.UserId)).Select(u => u.Value).ToList());
     }

Src/Fido2.Models/AssertionOptions.cs

@@ -41,7 +41,7 @@ public class AssertionOptions
     /// This OPTIONAL member contains a list of PublicKeyCredentialDescriptor objects representing public key credentials acceptable to the caller, in descending order of the caller’s preference(the first item in the list is the most preferred credential, and so on down the list)
     /// </summary>
     [JsonPropertyName("allowCredentials")]
-    public IReadOnlyList<PublicKeyCredentialDescriptor> AllowCredentials { get; set; } = Array.Empty<PublicKeyCredentialDescriptor>();
+    public IReadOnlyList<PublicKeyCredentialDescriptor> AllowCredentials { get; set; } = [];
 
     /// <summary>
     /// This member describes the Relying Party's requirements regarding user verification for the get() operation.
@@ -54,7 +54,7 @@ public class AssertionOptions
     /// This OPTIONAL member contains zero or more elements from <see cref="PublicKeyCredentialHint"/> to guide the user agent in interacting with the user. Note that the elements have type DOMString despite being taken from that enumeration.
     /// </summary>
     [JsonPropertyName("hints")]
-    public IReadOnlyList<PublicKeyCredentialHint> Hints { get; set; } = Array.Empty<PublicKeyCredentialHint>();
+    public IReadOnlyList<PublicKeyCredentialHint> Hints { get; set; } = [];
 
     /// <summary>
     /// This OPTIONAL member contains additional parameters requesting additional processing by the client and authenticator.

Src/Fido2.Models/Converters/EnumNameMapper.cs

@@ -41,7 +41,7 @@ public static IEnumerable<string> GetNames()
 
     private static FrozenDictionary<TEnum, string> GetIdToNameMap()
     {
-        var items = new List<KeyValuePair<TEnum, string>>();
+        List<KeyValuePair<TEnum, string>> items = [];
 
         foreach (var field in typeof(TEnum).GetFields(BindingFlags.Public | BindingFlags.Static))
         {

Src/Fido2.Models/CredentialCreateOptions.cs

@@ -67,7 +67,7 @@ public sealed class CredentialCreateOptions
 
 #nullable enable
 
-    private IReadOnlyList<PublicKeyCredentialHint> _hints = Array.Empty<PublicKeyCredentialHint>();
+    private IReadOnlyList<PublicKeyCredentialHint> _hints = [];
 
     /// <summary>
     /// Guides the user agent in interacting with the user. This OPTIONAL member contains zero or more elements from <see cref="PublicKeyCredentialHint" />.
@@ -126,8 +126,8 @@ public static CredentialCreateOptions Create(
         AttestationConveyancePreference attestationConveyancePreference,
         IReadOnlyList<PublicKeyCredentialDescriptor> excludeCredentials,
         AuthenticationExtensionsClientInputs? extensions,
-        IReadOnlyList<PubKeyCredParam> pubKeyCredParams)
-
+        IReadOnlyList<PubKeyCredParam> pubKeyCredParams)
+
     {
         return new CredentialCreateOptions
         {
@@ -184,8 +184,8 @@ public sealed class PubKeyCredParam(
     public static readonly PubKeyCredParam PS384 = new(COSE.Algorithm.PS384);
     public static readonly PubKeyCredParam PS512 = new(COSE.Algorithm.PS512);
     public static readonly PubKeyCredParam Ed25519 = new(COSE.Algorithm.EdDSA);
-    public static readonly PubKeyCredParam RS1 = new(COSE.Algorithm.RS1);
-
+    public static readonly PubKeyCredParam RS1 = new(COSE.Algorithm.RS1);
+
     /// <summary>
     /// The default algorithms supported by the library
     /// </summary>

Src/Fido2/Asn1Element.cs

@@ -162,7 +162,7 @@ public static Asn1Element Decode(ReadOnlyMemory<byte> data)
 
     private static List<Asn1Element> ReadElements(AsnReader reader)
     {
-        var elements = new List<Asn1Element>();
+        List<Asn1Element> elements = [];
 
         while (reader.HasData)
         {

Src/Fido2/AttestationFormat/FidoU2f.cs

@@ -85,7 +85,7 @@ .. publicKeyU2F
 
         // 7. Optionally, inspect x5c and consult externally provided knowledge to determine whether attStmt conveys a Basic or AttCA attestation
 
-        var trustPath = new X509Certificate2[1] { attCert };
+        X509Certificate2[] trustPath = [attCert];
 
         return new(new VerifyAttestationResult(AttestationType.AttCa, trustPath));
     }

Src/Fido2/Cbor/CborArray.cs

@@ -7,7 +7,7 @@ public sealed class CborArray : CborObject, IEnumerable<CborObject>
 {
     public CborArray()
     {
-        Values = new List<CborObject>();
+        Values = [];
     }
 
     public CborArray(List<CborObject> values)

Src/Fido2/Cbor/CborObject.cs

@@ -86,7 +86,7 @@ private static CborArray ReadArray(CborReader reader)
 
         var items = count != null
             ? new List<CborObject>(count.Value)
-            : new List<CborObject>();
+            : [];
 
         while (!(reader.PeekState() is CborReaderState.EndArray or CborReaderState.Finished))
         {

Src/Fido2/GetAssertionOptionsParams.cs

@@ -22,7 +22,7 @@ public sealed class GetAssertionOptionsParams
     ///
     /// The list is ordered in descending order of preference: the first item in the list is the most preferred credential, and the last is the least preferred.
     /// </summary>
-    public IReadOnlyList<PublicKeyCredentialDescriptor> AllowedCredentials { get; init; } = Array.Empty<PublicKeyCredentialDescriptor>();
+    public IReadOnlyList<PublicKeyCredentialDescriptor> AllowedCredentials { get; init; } = [];
 
     /// <summary>
     /// This OPTIONAL member specifies the Relying Party's requirements regarding user verification for the get() operation. The value SHOULD be a member of UserVerificationRequirement but client platforms MUST ignore unknown values, treating an unknown value as if the member does not exist. Eligible authenticators are filtered to only those capable of satisfying this requirement.

Src/Fido2/Metadata/ConformanceMetadataRepository.cs

@@ -82,7 +82,7 @@ public async Task<MetadataBLOBPayload> GetBLOBAsync(CancellationToken cancellati
             Entries = []
         };
 
-        var entries = new List<MetadataBLOBPayloadEntry>();
+        List<MetadataBLOBPayloadEntry> entries = [];
 
         foreach (var blobUrl in conformanceEndpoints)
         {