SupportedFeatures

Supported C# Features Matrix

This document provides a comprehensive list of C# features, .NET APIs, and patterns supported by the eQuantic.UI compiler.

Legend

✅ Full Support: Transpiles to equivalent JavaScript behavior.

⚠️ Partial Support: Works with caveats or minor differences.

🚧 Planned: On the roadmap.

❌ Not Supported: fundamentally incompatible logic (e.g., blocking I/O, unsafe pointers).

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🏗️ Core Language Features

Feature	Status	Notes
Classes & Structs	✅	Transpiled to ES6 Classes.
Interfaces	✅	Used for TypeScript type checking (erased at runtime).
Enums	✅	Transpiled to JS Objects (bidirectional mapping).
Generics	✅	Fully supported (erased at runtime).
Extension Methods	✅	Resolved via Semantic Model and transpiled to direct calls.
Async / Await	✅	Maps to async / await and Promise.
Lambda Expressions	✅	Maps to Arrow Functions () => {}.
Pattern Matching	✅	is patterns, Property Patterns, Recursive Patterns.
String Interpolation	✅	Maps to Template Literals `${var}`.
Null-Coalescing	✅	?? and ??= mapped to JS equivalents.
Object Initializers	✅	new Obj { Prop = 1 }.
Collection Initializers	✅	new List<int> { 1, 2 } maps to [1, 2].
Deconstruction	✅	var (a, b) = tuple maps to [a, b] = tuple.
Local Functions	✅	Transpiled to inner functions.
Records (with)	✅	Maps to object spread { ...src, prop: val }.
typeof	✅	Maps to type name string literal.
base calls	✅	Maps to super keyword.
cast & as	✅	Maps to JS passthrough/truncation.
sizeof	✅	Maps to C# primitive sizes.
Anonymous Methods	✅	delegate(...) { ... } maps to arrow functions.
stackalloc	✅	Maps to Typed Arrays (e.g., Int32Array).
yield return	✅	Maps to JS Generator Functions (function*).
lock	⚠️	Transpiled to a no-op block (JS is single-threaded).

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🔄 LINQ Support

The compiler includes specialized strategies for nearly all LINQ methods.

Logic	Methods	Status
Filtering	Where, OfType	✅
Projection	Select, SelectMany, Cast	✅
Partitioning	Skip, Take, SkipWhile, TakeWhile	✅
Ordering	OrderBy, OrderByDescending, ThenBy, Reverse	✅
Aggregation	Count, Sum, Min, Max, Average, Aggregate	✅
Quantifiers	Any, All, Contains	✅
Sets	Distinct, DistinctBy, Union, Intersect, Except, Concat	✅
Elements	First, FirstOrDefault, Single, Last, ElementAt	✅
Utility	SequenceEqual, DefaultIfEmpty	✅
Conversion	ToList, ToArray, ToDictionary, ToHashSet	✅
Grouping/Join	GroupBy, Join, Zip	✅

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📦 .NET Types (BCL)

We map common .NET types to their JavaScript equivalents.

Primitives

.NET Type	JavaScript Equivalent
string	String
int, double, float	Number
bool	Boolean
object	Object
dynamic	any

System.String

• ✅ Join, Format
• ✅ IsNullOrEmpty, IsNullOrWhiteSpace
• ✅ Split, Replace, Substring, Trim
• ✅ ToLower, ToUpper, StartsWith, EndsWith

System.DateTime & TimeSpan

• ✅ DateTime.Now, DateTime.UtcNow mapped to new Date().
• ✅ Year, Month, Day, Hour... properties.
• ✅ AddDays, AddHours... methods.
• ✅ ToString() (basic formatting).
• ✅ TimeSpan.FromMilliseconds... mapped to numeric milliseconds.

System.Collections.Generic

• ✅ List<T> → Javascript Array []
• ✅ Dictionary<TKey, TValue> → Javascript Object {} or Map (depending on usage).
• ✅ HashSet<T> → Javascript Set.
• ✅ Queue<T>, Stack<T> → Javascript Array methods (push/shift/pop).

System.Threading.Tasks

• ✅ Task, Task<T> → Promise.
• ✅ Task.Delay → setTimeout wrapper.
• ✅ Task.WhenAll, Task.WhenAny.
• ⚠️ Task.Run executes on the main thread (microtask), NOT a background thread.

Other Utilities

• ✅ Console.WriteLine → console.log.
• ✅ Math.* (Min, Max, Abs, Round, etc.) → Math.*.
• ✅ Guid (NewGuid, Empty, Parse) → crypto.randomUUID().
• ✅ Regex → JavaScript RegExp.

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⚠️ Limitations & Caveats

1. Blocking Code:

   • ❌ .Wait(), .Result on Tasks are NOT supported. You must use await. Blocking the main thread freezes the browser UI.

2. Reflection:

   • ❌ System.Reflection is largely unsupported.
   • ✅ typeof(T).Name and nameof(...) are supported constants.

3. File System:

   • ❌ System.IO (File, Directory) is not strictly forbidden but will fail at runtime in the browser.
   • Use Server Actions to handle file operations.

4. Numbers:

   • ⚠️ JavaScript uses 64-bit floating point for all numbers. long (64-bit int) precision may be lost for values > 2^53.
   • decimal is treated as number (double), so currency precision logic should happen on the Server.

5. Thread Safety:

   • Since JS is single-threaded, lock statements are compiled away (ignored).
   • Thread.Sleep is not supported (use Task.Delay).