code: function resolveSources() {
    const sources = [
      ...resolveEnvSources('NODE_PATH'),
      ...resolveEnvSources('BROWSER_PATH'),
      // Get global path from npm config
      path.join(
        process.env.npm_config_prefix || exec('npm config get prefix', { encoding: 'utf8' }).replace('\n', ''),
        'lib/node_modules'
      )
    ];
  
    return unique(sources.map(source => path.resolve(source)));
  }
docs: Resolve sources
  @returns {Array}