feat: add bun support

packages/bun/LICENSE.md

@@ -0,0 +1 @@
+../../LICENSE.md

packages/bun/README.md

@@ -0,0 +1,3 @@
+# workflow/bun
+
+The docs have moved! Refer to them [here](https://useworkflow.dev/)

packages/bun/package.json

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+{
+  "name": "@workflow/bun",
+  "version": "4.0.1-beta.1",
+  "description": "Bun integration for Workflow DevKit",
+  "type": "module",
+  "main": "dist/index.js",
+  "files": [
+    "dist"
+  ],
+  "publishConfig": {
+    "access": "public"
+  },
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/vercel/workflow.git",
+    "directory": "packages/bun"
+  },
+  "exports": {
+    ".": "./dist/index.js"
+  },
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch",
+    "clean": "tsc --build --clean && rm -rf dist"
+  },
+  "dependencies": {
+    "@swc/core": "1.11.24",
+    "@workflow/cli": "workspace:*",
+    "@workflow/core": "workspace:*",
+    "@workflow/swc-plugin": "workspace:*",
+    "exsolve": "^1.0.7",
+    "pathe": "^2.0.3"
+  },
+  "devDependencies": {
+    "@types/bun": "^1.3.1",
+    "@types/node": "catalog:",
+    "@workflow/tsconfig": "workspace:*"
+  }
+}

packages/bun/src/index.ts

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+import { mkdir } from 'node:fs/promises';
+import { join } from 'node:path';
+import { transform } from '@swc/core';
+import { BaseBuilder } from '@workflow/cli/dist/lib/builders/base-builder';
+import type { WorkflowConfig } from '@workflow/cli/dist/lib/config/types';
+import type { BunPlugin } from 'bun';
+
+export function workflowPlugin(): BunPlugin {
+  return {
+    name: 'workflow-transform',
+    async setup(build) {
+      // Build workflows on startup
+      await new LocalBuilder().build();
+
+      build.onLoad({ filter: /\.(ts|tsx|js|jsx)$/ }, async (args) => {
+        const source = await Bun.file(args.path).text();
+        // Optimization: Skip files that do not have any directives
+        if (!source.match(/(use step|use workflow)/)) {
+          return { contents: source };
+        }
+        const result = await transform(source, {
+          filename: args.path,
+          jsc: {
+            experimental: {
+              plugins: [
+                [require.resolve('@workflow/swc-plugin'), { mode: 'client' }],
+              ],
+            },
+          },
+        });
+        return { contents: result.code, loader: 'ts' };
+      });
+    },
+  };
+}
+
+const CommonBuildOptions = {
+  buildTarget: 'next' as const, // unused in base
+  stepsBundlePath: '', // unused in base
+  workflowsBundlePath: '', // unused in base
+  webhookBundlePath: '', // unused in base
+};
+
+export class LocalBuilder extends BaseBuilder {
+  #outDir: string;
+  constructor(config?: Partial<WorkflowConfig>) {
+    const outDir = join(config?.workingDir ?? process.cwd(), 'workflow');
+    super({
+      ...CommonBuildOptions,
+      dirs: config?.dirs ?? ['./workflows'],
+      workingDir: config?.workingDir ?? process.cwd(),
+    });
+    this.#outDir = outDir;
+  }
+
+  override async build(): Promise<void> {
+    const inputFiles = await this.getInputFiles();
+    await mkdir(this.#outDir, { recursive: true });
+
+    await this.createWorkflowsBundle({
+      outfile: join(this.#outDir, 'workflows.mjs'),
+      bundleFinalOutput: false,
+      format: 'esm',
+      inputFiles,
+    });
+
+    await this.createStepsBundle({
+      outfile: join(this.#outDir, 'steps.mjs'),
+      externalizeNonSteps: true,
+      format: 'esm',
+      inputFiles,
+    });
+
+    await this.createWebhookBundle({
+      outfile: join(this.#outDir, 'webhook.mjs'),
+      bundle: false,
+    });
+  }
+}

packages/bun/tsconfig.json

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+{
+  "extends": "@workflow/tsconfig/base.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "target": "es2022",
+    "module": "preserve",
+    "baseUrl": ".",
+    "moduleResolution": "bundler"
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "**/*.test.ts"]
+}

packages/bun/workflows/0_demo.ts

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+// import { FatalError } from 'workflow';
+
+export async function calc(n: number) {
+  'use workflow';
+  console.log('Simple workflow started');
+  n = await pow(n);
+  console.log('Simple workflow finished');
+  return n;
+}
+
+async function pow(a: number): Promise<number> {
+  'use step';
+  console.log('Running step pow with arg:', a);
+  return a * a;
+}

packages/bun/workflows/1_simple.ts

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+../../example/workflows/1_simple.ts

packages/bun/workflows/2_control_flow.ts

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+../../example/workflows/2_control_flow.ts

packages/bun/workflows/3_streams.ts

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+../../example/workflows/3_streams.ts

packages/bun/workflows/4_ai.ts

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+../../example/workflows/4_ai.ts

packages/bun/workflows/5_hooks.ts

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+../../example/workflows/5_hooks.ts

packages/bun/workflows/6_batching.ts

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+../../example/workflows/6_batching.ts

packages/bun/workflows/98_duplicate_case.ts

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+../../example/workflows/98_duplicate_case.ts

packages/bun/workflows/99_e2e.ts

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+../../example/workflows/99_e2e.ts

packages/workflow/package.json

@@ -28,6 +28,7 @@
       "default": "./dist/index.js"
     },
     "./api": "./dist/api.js",
+    "./bun": "./dist/bun.js",
     "./internal/errors": "./dist/internal/errors.js",
     "./internal/serialization": "./dist/internal/serialization.js",
     "./internal/builtins": "./dist/internal/builtins.js",
@@ -45,13 +46,16 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
+    "@types/bun": "^1.3.1",
+    "@workflow/bun": "workspace:*",
     "@workflow/cli": "workspace:*",
     "@workflow/core": "workspace:*",
     "@workflow/errors": "workspace:*",
-    "@workflow/typescript-plugin": "workspace:*",
-    "ms": "2.1.3",
     "@workflow/next": "workspace:*",
-    "@workflow/nitro": "workspace:*"
+    "@workflow/nitro": "workspace:*",
+    "@workflow/typescript-plugin": "workspace:*",
+    "bun": "^1.3.0",
+    "ms": "2.1.3"
   },
   "devDependencies": {
     "@types/ms": "^2.1.0",

packages/workflow/src/bun.ts

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+import { workflowPlugin } from '@workflow/bun';
+
+export default workflowPlugin;