Runtime Utilities

Utilities for runtime detection and environment access.

detectRuntime

Detect the current JavaScript runtime.

import { detectRuntime } from "nevr-env";

const runtime = detectRuntime();
// Returns: "node" | "browser" | "deno" | "bun" | "unknown"

switch (runtime) {
  case "node":
    // Node.js specific code
    break;
  case "browser":
    // Browser specific code
    break;
  case "deno":
    // Deno runtime
    break;
  case "bun":
    // Bun runtime
    break;
}

isServerRuntime

Check if running in a server environment.

import { isServerRuntime } from "nevr-env";

if (isServerRuntime()) {
  // Safe to access server secrets
  console.log(process.env.DATABASE_URL);
} else {
  // Browser - don't expose secrets!
}

Returns true for Node.js, Deno, and Bun. Returns false when window is defined (browser), except for Deno which can have window.

runtimeEnv

A Proxy-based environment object that works across runtimes. This is not a function — it's a Proxy object you use directly.

import { runtimeEnv } from "nevr-env";

// Automatically delegates to the correct env source:
// - process.env in Node.js
// - Deno.env in Deno
// - Bun.env in Bun
// - Internal shim in unknown runtimes

// Use directly (not as a function call)
const value = runtimeEnv.MY_VAR;

// Use as runtimeEnv in createEnv
import { createEnv } from "nevr-env";

const env = createEnv({
  server: {
    DATABASE_URL: z.string().url(),
  },
  // Pass the proxy object directly
  runtimeEnv: runtimeEnv,
});

TIP

In most cases, you can omit runtimeEnv entirely — createEnv uses runtimeEnv as the default when no runtimeEnv, runtimeEnvStrict, or experimental__runtimeEnv is provided.

getEnvVar

Safely get an environment variable with optional fallback.

import { getEnvVar } from "nevr-env";

// Returns undefined if not set
const apiKey = getEnvVar("API_KEY");

// With fallback value
const port = getEnvVar("PORT", "3000");

getBooleanEnvVar

Parse boolean environment variables.

import { getBooleanEnvVar } from "nevr-env";

// Parses: "0", "false", "no", "" -> false
// Everything else -> true
const debug = getBooleanEnvVar("DEBUG");

// With default (default is true)
const verbose = getBooleanEnvVar("VERBOSE", false);

ENV

Pre-configured environment accessor with common helpers.

import { ENV } from "nevr-env";

// Common getters
ENV.NODE_ENV;       // string (defaults to "development")
ENV.isProduction;   // boolean
ENV.isDevelopment;   // boolean
ENV.isTest;         // boolean
ENV.isCI;           // boolean

Property	Type	Description
NODE_ENV	string	Current NODE_ENV, defaults to "development"
isProduction	boolean	true when NODE_ENV === "production"
isDevelopment	boolean	true when NODE_ENV === "development" or "dev"
isTest	boolean	true when NODE_ENV === "test"
isCI	boolean	true when CI env var is truthy

Platform-Specific Examples

Node.js

import { createEnv } from "nevr-env";

const env = createEnv({
  server: { ... },
  runtimeEnv: process.env,
});

Vite

import { createEnv } from "nevr-env";

const env = createEnv({
  client: { ... },
  clientPrefix: "VITE_",
  runtimeEnv: import.meta.env,
});

Deno

import { createEnv } from "nevr-env";

const env = createEnv({
  server: { ... },
  runtimeEnv: Deno.env.toObject(),
});

Cloudflare Workers

import { createEnv } from "nevr-env";

export default {
  async fetch(request, env) {
    const validatedEnv = createEnv({
      server: { ... },
      runtimeEnv: env, // Platform bindings
    });
  },
};