Netlify build time configuration file.

netlify.toml

[build]
  publish = "dist"
  command = "npm run build"

# Production context: All deploys to the main
# repository branch will inherit these settings.
[context.production]
  [context.production.environment]
    NODE_ENV = "production"

# Specific branch context: Deploys from this branch
# will take these settings and override their
# current ones.

[context.development]
[context.development.environment]
  API_KEY = "<your-firebase-development-project-api-key>"
  AUTH_DOMAIN = "<your-firebase-development-project-auth-domain>"
  DATABASE_URL = "<your-firebase-development-project-database-url>"
  PROJECT_ID = "<your-firebase-development-project-id>"
  STORAGE_BUCKET = "<your-firebase-development-project-storage-bucket>"
  MESSENGER_SENDER_ID = "<your-firebase-development-project-messenger-sender-id>"