code: function envSet(loader, cfg, envCallback) {
    if (envModule.browser && cfg.browserConfig)
      envCallback(cfg.browserConfig);
    if (envModule.node && cfg.nodeConfig)
      envCallback(cfg.nodeConfig);
    if (envModule.dev && cfg.devConfig)
      envCallback(cfg.devConfig);
    if (envModule.build && cfg.buildConfig)
      envCallback(cfg.buildConfig);
    if (envModule.production && cfg.productionConfig)
      envCallback(cfg.productionConfig);
  }
docs: /*
  Extend config merging one deep only
  
  loader.config({
  some: 'random',
  config: 'here',
  deep: {
  config: { too: 'too' }
  }
  });
  
  <=>
  
  loader.some = 'random';
  loader.config = 'here'
  loader.deep = loader.deep || {};
  loader.deep.config = { too: 'too' };
  
  
  Normalizes meta and package configs allowing for:
  
  SystemJS.config({
  meta: {
  './index.js': {}
  }
  });
  
  To become
  
  SystemJS.meta['https://thissite.com/index.js'] = {};
  
  For easy normalization canonicalization with latest URL support.