@mono-labs/expo

Expo and EAS build utilities for Mono. Provides environment variable filtering, Expo config setup, and token replacement for Expo/React Native projects.

Installation

yarn add @mono-labs/expo

Peer dependency: expo >= 52 (optional)

API Reference

Config Setup

import { setUpConfig } from "@mono-labs/expo";

• setUpConfig(config) -- Transforms an Expo app.json config into a fully resolved ExpoConfig with environment variable injection. Filters NEXT_PUBLIC_* vars, sets up EAS project ID, and configures router settings.

Token Replacement

import { replaceTokens } from "@mono-labs/expo";

• replaceTokens(input, tokens) -- Replaces ${KEY} and $KEY patterns in a string using the provided tokens object. Data layer values take priority over environment variables.

Environment Filtering

import {
  filterUnwantedEnvVars,
  filterUnwantedEnvVarsEAS,
  generateNewEnvList
} from "@mono-labs/expo";

• filterUnwantedEnvVars(env) -- Minimal filtering for local development. Removes only npm_config_force.
• filterUnwantedEnvVarsEAS(env) -- Aggressive filtering for EAS cloud builds. Removes 50+ system and developer tool variables (Windows paths, VS Code, Git, Node internals, etc.) to keep the EAS build environment clean.
• generateNewEnvList(processEnv) -- Maps MONO_* prefixed environment variables to configured prefixes using the envMap from .mono/config.json. Variables containing SECRET in the name are excluded from mapping.

Subpath Exports

| Export | Description | |--------|-------------| | @mono-labs/expo | All utilities: replaceTokens, setUpConfig, filterUnwantedEnvVars, filterUnwantedEnvVarsEAS, generateNewEnvList | | @mono-labs/expo/tools | replaceTokens, setUpConfig | | @mono-labs/expo/cdk | replaceTokens, setUpConfig |

Development

Build the expo package:

yarn build:expo

This package depends on @mono-labs/project for config loading. Build project first if making changes to both.

See the Contributing guide for full development setup.