02-Examples.md

title	Examples
section	AngleSharp.Wasm

Example Code

This is a (growing) list of examples for every-day usage of AngleSharp.Wasm.

Basic Setup

var config = Configuration.Default.WithWasm();
using var context = BrowsingContext.New(config);
using var document = await context.OpenNewAsync();

Compile and Instantiate

var module = WebAssembly.Compile(context.Current!, wasmBytes);
var instance = WebAssembly.Instantiate(context.Current!, module);

Invoke an Exported Function

var result = instance.Invoke("answer");

You can also invoke through the export wrapper:

var exported = (WasmJsExportedFunction?)instance.Exports["answer"];
var result = exported?.Invoke();

Invoke an Exported Function with Arguments

var add = (WasmJsExportedFunction?)instance.Exports["add"];
var result = add?.Invoke(20, 22); // 42

Read Module Export and Import Metadata

foreach (var exportEntry in module.Exports())
{
	Console.WriteLine($"Export: {exportEntry.Name} ({exportEntry.Kind})");
}

foreach (var importEntry in module.Imports())
{
	Console.WriteLine($"Import: {importEntry.Module}.{importEntry.Name} ({importEntry.Kind})");
}

Read Custom Sections

var sections = module.CustomSections("meta");

foreach (var payload in sections)
{
	Console.WriteLine($"Section payload length: {payload.Length}");
}

Register Host Imports

var config = Configuration.Default
	.WithWasm()
	.WithWasmImports(_ =>
	{
		return new[]
		{
			new WasmImportFunction(
				"host",
				"answer",
				Array.Empty<WasmValueType>(),
				new[] { WasmValueType.Int32 },
				_ => 41),
		};
	});

With a module importing host.answer, an export such as answer_plus_one can now be invoked as expected.

Check for Missing Exports

var maybe = instance.Exports["does_not_exist"];

if (maybe is null)
{
	Console.WriteLine("Export not found.");
}

List Available Export Names

var keys = instance.Exports.Keys();