Environment variables

Any flag can fall back to an environment variable. Set env to the variable's name:

import { command, flag } from 'jinju';

command({
	description: 'Deploy',
	flags: {
		token: flag.string({ description: 'API token', env: 'API_TOKEN' }).required(),
		port: flag.number({ description: 'Port', env: 'PORT' }).default(8080),
		verbose: flag.count({ alias: 'v', description: 'Verbosity', env: 'VERBOSE' }),
	},
	run: ({ flags }) => {},
});

Priority

The command line wins, then the variable, then the default. A value from the variable satisfies .required().

Parsing

Values from the environment are parsed and validated like command-line values, so flag.number({ env: 'PORT' }) checks that PORT is a number. Errors name where the value came from:

error: Invalid value 'abc' for --port (from $PORT): must be a number

• flag.boolean accepts true/false, 1/0, yes/no and on/off, in any case.
• flag.count accepts a whole number: VERBOSE=2.
• Empty values (API_TOKEN=) count as unset.
• A .multiple() flag gets a single value from its variable.

Help

Help shows the variable after the description:

Flags:
  --token <string>  API token (required; env: API_TOKEN)

Where variables come from

Variables are read from process.env by default. Pass env to jinju() to supply them yourself, for example in tests:

const app = jinju({ commands: { deploy }, env: { API_TOKEN: 'test' } });

await app.run(['deploy']);