n/no-process-env | Bun Docs

When you read process.env all over the code, it's hard to list the variables the program needs, a misspelled name gives undefined without an error, and tests have to change the process's environment. Read the environment in one config file and import the values from there.

Configure#

Off by default. To turn it on:

bunfig.toml

[lint.rules]
"n/no-process-env" = "error" # or "warn"

Every option, set to its default:

bunfig.toml

[lint.rules]
"n/no-process-env" = ["error", {
  allowedVariables = [], # list of strings
}]

Examples#

example.js1 problem

if (process.env.NODE_ENV === "development") {
  enableLogging();
}

example.jsNo problems

import { config } from "./config";

if (config.env === "development") {
  enableLogging();
}

Options#

Option	Default	What it does
`allowedVariables`	`[]`	Names of variables you can read from `process.env`.

example.jswith { "allowedVariables": ["NODE_ENV"] }No problems

const isProduction = process.env.NODE_ENV === "production";
const mode = process.env["NODE_ENV"];

Other variables are still reported, and so is process.env by itself:

example.jswith { "allowedVariables": ["NODE_ENV"] }2 problems

const port = process.env.PORT;
const { NODE_ENV } = process.env;

When not to use it#

Turn it off for the one file that reads the environment, and in scripts and small tools where a config file is more than you need.