chore: enable WASM support (#430)

* chore: enable WASM support

* chore: add docs and changeset

.changeset/nasty-cars-attack.md

@@ -0,0 +1,6 @@
+---
+'@callstack/reassure-cli': patch
+'reassure': patch
+---
+
+feat: Experimental options to enable WebAssembly (--enable-wasm)

docusaurus/docs/troubleshooting.md

@@ -0,0 +1,18 @@
+---
+title: Troubleshooting
+sidebar_position: 5
+---
+
+### Handling `ReferenceError: WebAssembly is not defined`
+
+Reassure, by default, uses Node.js's `--jitless` flag to disable its optimizing compiler to increase test stability. This flag prevents WebAssembly (WASM) from running because of internal Node.js architecture. In some cases, you might still allow your tests to include code depending on WASM, e.g., the `fetch` method is implemented using WASM.
+
+In such cases, pass the `--enable-wasm` flag to Reassure CLI:
+
+```sh
+$ reassure --enable-wasm
+```
+
+This option will replace the Node.js `--jitless` flag with alternative flags to achieve a similar stabilizing effect.
+
+Note that this option is experimental and may negatively affect the stability of your tests.

packages/reassure-cli/src/commands/check-stability.ts

@@ -14,7 +14,12 @@ export const command: CommandModule<{}, CommonOptions> = {
   command: 'check-stability',
   describe: 'Checks how stable is the current machine by running measurements twice for the same code',
   builder: (yargs) => {
-    return applyCommonOptions(yargs);
+    return applyCommonOptions(yargs).option('enable-wasm', {
+      type: 'boolean',
+      default: false,
+      describe:
+        '(experimental) Enables WebAssembly support in tests by modifying Node flags. This may affect test stability.',
+    });
   },
   handler: (args) => run(args),
 };

packages/reassure-cli/src/commands/measure.ts

@@ -16,6 +16,7 @@ export interface MeasureOptions extends CommonOptions {
   branch?: string;
   commitHash?: string;
   testMatch?: string;
+  enableWasm?: boolean;
 }
 
 export async function run(options: MeasureOptions) {
@@ -64,15 +65,16 @@ export async function run(options: MeasureOptions) {
   const testRunnerArgs = process.env.TEST_RUNNER_ARGS ?? defaultArgs;
 
   const nodeArgs = [
-    '--jitless',
+    // Use less restrictive flags to allow running WASM code (e.g. `fetch`) in tests.
+    options.enableWasm ? '--no-opt --no-sparkplug' : '--jitless',
     '--expose-gc',
     '--no-concurrent-sweeping',
     '--max-old-space-size=4096',
     testRunnerPath,
     testRunnerArgs,
   ];
   logger.verbose('Running tests using command:');
-  logger.verbose(`$ node ${nodeArgs.join(' \\\n    ')}\n`);
+  logger.verbose(`$ node \\\n    ${nodeArgs.join(' \\\n    ')}\n`);
 
   const spawnInfo = spawnSync('node', nodeArgs, {
     shell: true,
@@ -145,6 +147,12 @@ export const command: CommandModule<{}, MeasureOptions> = {
         type: 'string',
         default: undefined,
         describe: 'Run performance tests for a specific test file',
+      })
+      .option('enable-wasm', {
+        type: 'boolean',
+        default: false,
+        describe:
+          '(experimental) Enables WebAssembly support in tests by modifying Node flags. This may affect test stability.',
       });
   },
   handler: (args) => run(args),