Compresses the wasm binary to reduce its size when hosted

packages/komodo_defi_framework/web/res/kdflib_bootstrapper.js

@@ -1,6 +1,7 @@
 // @ts-check
 import init, { LogLevel } from "../kdf/bin/kdflib.js";
 import * as kdflib from "../kdf/bin/kdflib.js";
+import { loadCompressedWasm } from "./wasm_loader.js";
 
 const LOG_LEVEL = LogLevel.Info;
 
@@ -42,7 +43,11 @@ kdf.init_wasm = async function () {
     }
 
     kdf._isInitializing = true;
-    kdf._initPromise = init()
+    const gzipWasmBinPath = "../kdf/bin/kdflib_bg.wasm.gz"
+    const gzipKdfBinUrl = new URL(gzipWasmBinPath, import.meta.url);
+    const kdfBinBuffer = await loadCompressedWasm(gzipKdfBinUrl);
+
+    kdf._initPromise = init(kdfBinBuffer)
         .then(() => {
             kdf._isInitializing = false;
             kdf._initPromise = null;

packages/komodo_defi_framework/web/res/wasm_loader.js

@@ -0,0 +1,66 @@
+export async function loadCompressedWasm(url) {
+    try {
+        // Fetch the compressed WASM file
+        const response = await fetch(url.toString(), {
+            method: 'GET',
+            cache: 'force-cache', // Use cache if available
+        });
+
+        if (!response.ok) {
+            throw new Error(
+                `Failed to fetch compressed WASM: ${response.status} ${response.statusText}`
+            );
+        }
+
+        // Check if browser supports DecompressionStream
+        if (!('DecompressionStream' in globalThis)) {
+            throw new Error(
+                'Browser does not support DecompressionStream API. Please use a modern browser.'
+            );
+        }
+
+        // Ensure response.body is available
+        if (!response.body) {
+            throw new Error(
+                'Response body is not available. Streaming not supported or body already consumed.'
+            );
+        }
+
+        // Create a decompression stream for gzip
+        const decompressionStream = new DecompressionStream('gzip');
+
+        // Pipe the response through the decompression stream
+        const decompressedStream = response.body.pipeThrough(decompressionStream);
+
+        // Read the decompressed stream into an ArrayBuffer
+        const reader = decompressedStream.getReader();
+        const chunks = [];
+
+        while (true) {
+            const { done, value } = await reader.read();
+            if (done) break;
+            chunks.push(value);
+        }
+
+        // Combine all chunks into a single ArrayBuffer
+        const totalLength = chunks.reduce((acc, chunk) => acc + chunk.length, 0);
+        const result = new Uint8Array(totalLength);
+        let offset = 0;
+
+        for (const chunk of chunks) {
+            result.set(chunk, offset);
+            offset += chunk.length;
+        }
+
+        //console.log(`WASM decompressed: ${(totalLength / 1024 / 1024).toFixed(2)} MB`);
+
+        return result.buffer;
+    } catch (error) {
+        console.error('Failed to load compressed WASM:', error);
+        throw error;
+    }
+}
+
+export function supportsGzipDecompression() {
+    return 'DecompressionStream' in globalThis;
+}

packages/komodo_wallet_build_transformer/lib/src/steps/copy_platform_assets_build_step.dart

@@ -140,7 +140,6 @@ class CopyPlatformAssetsBuildStep extends BuildStep {
       await for (final entity in sourceDir.list(recursive: true)) {
         if (entity is File) {
           final relativePath = path.relative(entity.path, from: sourceDir.path);
-          final destFile = File(path.join(destDir.path, relativePath));
 
           if (skipDir != null &&
               path.isWithin(
@@ -151,13 +150,44 @@ class CopyPlatformAssetsBuildStep extends BuildStep {
             continue;
           }
 
-          if (!destFile.parent.existsSync()) {
-            destFile.parent.createSync(recursive: true);
+          // Check if this is a WASM file that needs compression
+          if (path.basename(entity.path) == 'kdflib_bg.wasm') {
+            // Compress and save as .wasm.gz
+            final destFile = File(path.join(destDir.path, relativePath + '.gz'));
+
+            if (!destFile.parent.existsSync()) {
+              destFile.parent.createSync(recursive: true);
+            }
+            if (destFile.existsSync()) {
+              destFile.deleteSync();
+            }
+
+            // Read, compress, and write
+            final wasmBytes = await entity.readAsBytes();
+            final originalSize = wasmBytes.length;
+            final compressedBytes = gzip.encode(wasmBytes);
+            final compressedSize = compressedBytes.length;
+            await destFile.writeAsBytes(compressedBytes);
+
+            final compressionRatio =
+                ((originalSize - compressedSize) / originalSize * 100).toStringAsFixed(1);
+            _log.info(
+              'Compressed kdflib_bg.wasm during copy: '
+              '${originalSize} bytes -> ${compressedSize} bytes '
+              '($compressionRatio% reduction)',
+            );
+          } else {
+            // Normal file copy
+            final destFile = File(path.join(destDir.path, relativePath));
+
+            if (!destFile.parent.existsSync()) {
+              destFile.parent.createSync(recursive: true);
+            }
+            if (destFile.existsSync()) {
+              destFile.deleteSync();
+            }
+            entity.copySync(destFile.path);
           }
-          if (destFile.existsSync()) {
-            destFile.deleteSync();
-          }
-          entity.copySync(destFile.path);
         }
       }
       _log.info(