Browser

In the browser there is no filesystem and no process.env. Your bundler inlines configuration at build time, and you seed a PortableSource from it, then read with the same typed API as everywhere else.

Import from envapt. The package export conditions resolve a node-free portable build in the browser automatically, so the same import works in local dev and in the bundle.

import { Envapter } from 'envapt';

Envapter.getBoolean('FEATURE_BETA', false); // readers work
Envapter.baseDir = '/tmp'; // warns once and no-ops in the browser

Seed from your bundler

Bundlers replace build-time env references with string literals: Vite exposes them on import.meta.env, webpack through DefinePlugin. Pass that object to PortableSource, then read the values typed.

import { Envapter, PortableSource, Converters } from 'envapt';

Envapter.useSource(new PortableSource(import.meta.env));

const apiUrl = Envapter.getUsing('VITE_API_URL', Converters.Url); // URL, not a raw string
const beta = Envapter.getBoolean('VITE_ENABLE_BETA', false); // boolean

import.meta.env.VITE_API_URL is a string; Envapter.getUsing('VITE_API_URL', Converters.Url) returns a URL, and getBoolean returns a boolean. PortableSource snapshots the object and JSON-stringifies non-string values, so you can read Vite's boolean DEV and PROD flags too.

Environment detection

Envapter.environment and the isProduction / isDevelopment / isTest helpers also read MODE, which Vite sets to development, production, or your --mode value. Because you bind import.meta.env, they work with no extra wiring. See Environment.

No filesystem

PortableSource snapshots its object at construction, so mutating that object afterward does not change what envapt reads. There is no .env cascade in the browser, and reading before you bind a source throws NoSourceBound. See Sources.

Decorators

The default @Envapt accessor decorators work in the browser build, the legacy envapt/legacy form needs a compile step.

For the providers and the contract see Sources.