source: trip-planner-front/node_modules/npm-run-path/index.js

'use strict';
const path = require('path');
const pathKey = require('path-key');

module.exports = opts => {
        opts = Object.assign({
                cwd: process.cwd(),
                path: process.env[pathKey()]
        }, opts);

        let prev;
        let pth = path.resolve(opts.cwd);
        const ret = [];

        while (prev !== pth) {
                ret.push(path.join(pth, 'node_modules/.bin'));
                prev = pth;
                pth = path.resolve(pth, '..');
        }

        // ensure the running `node` binary is used
        ret.push(path.dirname(process.execPath));

        return ret.concat(opts.path).join(path.delimiter);
};

module.exports.env = opts => {
        opts = Object.assign({
                env: process.env
        }, opts);

        const env = Object.assign({}, opts.env);
        const path = pathKey({env});

        opts.path = env[path];
        env[path] = module.exports(opts);

        return env;
};