Lazy-load storage plugins to avoid side effects on import

[whaaaley]

Problem

Importing natural for NLP features (tokenizers, stemmers, TF-IDF, etc.) eagerly loads all five storage plugins (Postgres, MongoDB, Redis, Memcached, File) at module scope in StorageBackend.js. Each plugin calls require('dotenv').config(), which reads .env files from disk, mutates process.env, and as of dotenv v17, logs promotional messages to stdout on every call.

This means anyone who imports natural for basic NLP gets unwanted console output, filesystem reads, and environment mutation -- even if they never use storage. Since dotenv is only used by the storage plugins, lazy-loading them eliminates these side effects entirely for the majority of users.

Here is what our production logs look like on every server restart (Fly.io, ord region). We only use natural for tokenizing and stemming:

[dotenv@17.3.1] injecting env (0) from .env -- tip: ⚡️ secrets for agents: https://dotenvx.com/as2
[dotenv@17.3.1] injecting env (0) from .env -- tip: ⚙️  load multiple .env files with { path: ['.env.local', '.env'] }
[dotenv@17.3.1] injecting env (0) from .env -- tip: 🛡️ auth for agents: https://vestauth.com
[dotenv@17.3.1] injecting env (0) from .env -- tip: ⚙️  write to custom object with { processEnv: myObject }
[dotenv@17.3.1] injecting env (0) from .env -- tip: ⚙️  specify custom .env file path with { path: '/custom/path/.env' }

Five log lines, one per storage plugin, injecting 0 env vars, with ads for a product we don't use. There's no way to silence these because the quiet option only works when you call dotenv.config() yourself -- not when a transitive dependency calls it.

For context, dotenv v17's default logging behavior has been a widespread issue:

• motdotla/dotenv#899 - "Why am I getting ads in my terminal?"
• motdotla/dotenv#918 - "Why is this library muddying my logs with ads"
• motdotla/dotenv#881 - "Setting quiet: true is ineffective because other libs use dotenv"
• motdotla/dotenv#909 - "Advertising in runtime logs"
• motdotla/dotenv#904 - "Remove the injecting env tip. Absolutely annoying!"

Solution

Move the require() calls from the top of StorageBackend.js into the switch inside setStorageType(). Storage plugins are now loaded on demand only when a user explicitly creates a storage backend.

This is a non-breaking change. Users of the storage feature see no difference in behavior.

Testing

All 858 existing specs pass.

[whaaaley]

This also addresses #754. The punycode deprecation warning comes from mongoose, which is pulled in by the MongoDB storage plugin. With lazy loading, users who don't call setStorageType('mongodb') never load mongoose and never see the warning.

If you're open to it, another option would be moving mongoose, pg, redis, and memjs to peerDependencies or optionalDependencies so they're not installed at all unless the user explicitly adds them. Or the storage backends could be a separate package entirely. Happy to help with either approach.