Writing custom stubs

When SootSim doesn’t have a builtin stub for a package you use, you can provide your own.

Config-based stubs

Noop (empty module)

// sootsim.config.ts
import { defineConfig } from 'sootsim/config'

export default defineConfig({
  modules: {
    'react-native-analytics': 'noop',
  },
})

File stub

// stubs/camera.ts
export async function takePicture() {
  return { uri: 'https://placekitten.com/400/400', width: 400, height: 400 }
}
export async function requestPermission() {
  return { status: 'granted' }
}

// sootsim.config.ts
import { defineConfig } from 'sootsim/config'

export default defineConfig({
  modules: {
    'react-native-camera': { file: './stubs/camera.ts' },
  },
})

Inline stub

import { defineConfig } from 'sootsim/config'

export default defineConfig({
  modules: {
    'react-native-config': {
      inline: {
        API_URL: 'http://localhost:3000',
        ENV: 'development',
      },
    },
  },
})

Guidelines

Export the same named exports as the original package
Use real browser APIs where possible (camera → getUserMedia, clipboard → navigator.clipboard)
For UI components, return a View/Text wrapper that renders children
For hooks, return sensible defaults
Never stub pure JS packages — they work as-is

Registry & Overrides