feat: add bun support

[adriandlam]

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Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	npm/​@​types/​bun@​1.3.1

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[vercel]

Suggested change

	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';
	import { createRequire } from 'module';
	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';
	const require = createRequire(import.meta.filename);

The code uses require.resolve() without importing or initializing require, which will cause a runtime error in ES modules.

View Details

Analysis

Missing require initialization in Bun plugin causes runtime error in ES module

What fails: packages/bun/src/index.ts calls require.resolve('@workflow/swc-plugin') on line 26 without initializing require, which causes ReferenceError: require is not defined at runtime when the Bun plugin attempts to transform files with workflow directives.

How to reproduce:

1. Import the @workflow/bun package (which has "type": "module" in package.json)
2. Call the workflowPlugin() function to register the Bun plugin
3. Process any TypeScript/JavaScript file containing "use workflow" or "use step" directives
4. The plugin's build.onLoad() handler will execute and throw: ReferenceError: require is not defined

Expected behavior: The plugin should successfully resolve the SWC plugin path and transform the file. Per Node.js ES Module documentation, require must be explicitly created in ES modules using createRequire from the 'module' package.

Root cause: The file uses ES module syntax (import statements) and declares "type": "module" in package.json, but attempts to use the global require function which is only available in CommonJS modules. This contrasts with @workflow/next which uses "type": "commonjs" and can use require directly.

Solution: Import createRequire from 'module' and initialize the require function at the module level, following the pattern established in packages/cli/src/lib/builders/apply-swc-transform.ts.

[versecafe]

@adriandlam What's required to get bun support for workflows over the line?

[adriandlam]

hey @versecafe! I'm just working on other integrations right now and will take a look at this again after. You can take a look at #162 if you'd like to get started on where I left off.

The main problem is finding a way to tap into Bun's HMR to bundle the workflows/steps/webhook routes.

Open to thoughts!