index.js

'use strict';
const execa = require('execa');
const stripAnsi = require('strip-ansi');
const defaultShell = require('default-shell');

const args = [
	'-ilc',
	'echo -n "_SHELL_ENV_DELIMITER_"; env; echo -n "_SHELL_ENV_DELIMITER_"; exit'
];

const parseEnv = env => {
	env = env.split('_SHELL_ENV_DELIMITER_')[1];
	const ret = {};

	for (const line of stripAnsi(env).split('\n').filter(line => Boolean(line))) {
		const [key, ...values] = line.split('=');
		ret[key] = values.join('=');
	}

	return ret;
};

module.exports = async shell => {
	if (process.platform === 'win32') {
		return process.env;
	}

	try {
		const {stdout} = await execa(shell || defaultShell, args);
		return parseEnv(stdout);
	} catch (error) {
		if (shell) {
			throw error;
		} else {
			return process.env;
		}
	}
};

module.exports.sync = shell => {
	if (process.platform === 'win32') {
		return process.env;
	}

	try {
		const {stdout} = execa.sync(shell || defaultShell, args);
		return parseEnv(stdout);
	} catch (error) {
		if (shell) {
			throw error;
		} else {
			return process.env;
		}
	}
};